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Mark Jensen is Co-Chair of the firm-wide Special Matters and Government Investigations practice group and Managing Partner of King & Spalding’s Washington, D.C. office. He specializes in high-profile investigations, white-collar litigation for companies and individuals, regulatory enforcement actions, internal reviews and compliance counseling. Mark’s practice has been nationally acclaimed, and he has been widely recognized for the positive results he obtains for an array of clients in criminal and civil cases, including governmental investigations, prosecutions and False Claims Act civil litigation.  Law360 has described him as “one of the most sought-after corporate defenders in the country” and the Legal 500 as “an extremely accomplished lawyer.”  Clients selected him for the prestigious BTI Client Service All-Stars Award, commending his judgment, “practical approach” and knowing “what to fight for.”  He also has been ranked by The Best Lawyers in America 2025 and named a 2025 Lawdragon 500 Leading Litigator in America.

Mark defends leading companies and senior executives in litigation in federal and state courts, as well as in prosecutions and investigations by U.S. Attorneys, multiple divisions of the U.S. Department of Justice, the Securities and Exchange Commission, Food and Drug Administration, Environmental Protection Agency, National Oceanic and Atmospheric Administration, and Congress.

Mark’s litigation experience includes criminal and civil issues relating to pharmaceuticals, biotechnology, laboratory testing and medical devices; Foreign Corrupt Practices Act matters; tax and accounting-related fraud; environmental and wildlife prosecutions; and federal contracting and procurement fraud.

In addition to his current role as Managing Partner, Mark has served in numerous other firm leadership roles.  Elected by his partners to the firm’s managing Policy Committee, he also has served on the firm-wide Lateral Partner Committee and the Performance Management and Compensation Committee.  He also served as Lateral Partner Hiring Lead for the firm-wide Government Matters Practice Group, and previously was the Hiring Partner and Deputy Managing Partner for the D.C. office.

Legal 500 U.S. recommended Mark for white-collar criminal defense in 2024 and previous years, describing him as “brilliant and creative” with “an excellent track record.”  Benchmark Litigation recognized him as a “Litigation Star” in its 2023 and previous editions.  LMG Life Sciences named Mark a Life Sciences Star for White Collar/Government Investigations in its 2023 and previous editions, including shortlisting him multiple times as one of six lawyers nationwide for Government Investigations Attorney of the Year.



Full Bio

Credentials

J.D., Harvard University, cum laude

B.A., Indiana University, summa cum laude, Phi Beta Kappa

District of Columbia

U.S. Court of Appeals for the Seventh Circuit

U.S. District Court for the Northern District of Illinois

U.S. District Court for the Southern District of Indiana

Law Clerk, Hon. Sarah Evans Barker, U.S. District Court for the Southern District of Indiana

"Mark is the best in the business. The combination of experience, education and demeanor is outstanding."


2024 Client Feedback to Ranking Guide

"I thank him and his team every day. I can't say anything stronger than that."


2024 Client Feedback to Ranking Guide

"few firms that can match the experience or success rate that Mark and the K&S team bring...the first call we make."


2024 Client Feedback to Ranking Guide

Litigation Star: White Collar and Civil Litigation


BENCHMARK LITIGATION (2023 and previous editions)

One of six lawyers nationwide shortlisted for Government Investigations Attorney of the Year


LMG Life Sciences (2023 & 2022)

White-Collar Criminal Defense, Leading Lawyer


Legal 500 U.S. (2024 and previous editions)

LMG Life Sciences Star: White Collar/Government Investigations


LMG Life Sciences (2023 and previous editions)

What Clients Say: “Mark has an ingrained understanding of the practical approach we favor.” “He knows what to fight for."


BTI Consulting Group (2020)

BTI Client Service All-Star


BTI Consulting Group (2020)

“Quickly Made a Name for Himself as an Extremely Accomplished Lawyer”...“An Excellent Track Record”...“Creative”


Legal 500 U.S. (2011)

“One of Five U.S. White-Collar Lawyers to Watch”


Law360 (2011)

“One of the Most Sought-After Corporate Defenders in the Country”


Law360 (2011)

Close

Recognition

"Mark is the best in the business. The combination of experience, education and demeanor is outstanding."


2024 Client Feedback to Ranking Guide

"I thank him and his team every day. I can't say anything stronger than that."


2024 Client Feedback to Ranking Guide

"few firms that can match the experience or success rate that Mark and the K&S team bring...the first call we make."


2024 Client Feedback to Ranking Guide

Litigation Star: White Collar and Civil Litigation


BENCHMARK LITIGATION (2023 and previous editions)

One of six lawyers nationwide shortlisted for Government Investigations Attorney of the Year


LMG Life Sciences (2023 & 2022)

White-Collar Criminal Defense, Leading Lawyer


Legal 500 U.S. (2024 and previous editions)

LMG Life Sciences Star: White Collar/Government Investigations


LMG Life Sciences (2023 and previous editions)

What Clients Say: “Mark has an ingrained understanding of the practical approach we favor.” “He knows what to fight for."


BTI Consulting Group (2020)

BTI Client Service All-Star


BTI Consulting Group (2020)

“Quickly Made a Name for Himself as an Extremely Accomplished Lawyer”...“An Excellent Track Record”...“Creative”


Legal 500 U.S. (2011)

“One of Five U.S. White-Collar Lawyers to Watch”


Law360 (2011)

“One of the Most Sought-After Corporate Defenders in the Country”


Law360 (2011)

Matters

Represented a variety of life science and health care companies, as well as individual employees, officers, consultants and medical professionals, in criminal and civil litigation by multiple U.S. Attorneys Offices, DOJ, HHS-OIG, qui tam Relators, state attorneys general and national Medicaid fraud control units, regarding alleged “off-label” promotion, unlawful inducements and other sales, marketing, pricing and development activities. Successfully represented a variety of clients in these investigations, including prevailing on motions to dismiss False Claims Act lawsuits in federal district court and resolving successfully the largest U.S. False Claims Act matter involving a medical device and kickback allegations.

Represented Janssen Pharmaceuticals, Johnson & Johnson and related companies in a 2013 global resolution of multiple DOJ investigations, including the negotiation and settlement of False Claims Act; Food, Drug & Cosmetic Act; and related allegations. The False Claims Act component of the resolution included seven qui tam complaints venued in the E.D.Pa., D.Mass. and N.D.Ca. Also led the related resolution of administrative claims by HHS-OIG through the company’s Corporate Integrity Agreement. In parallel state litigation, led the resolution of multi-state and individual state consumer protection claims and lawsuits, as well as state claims alleged by Medicaid Fraud Control Units and similar attorneys general and state representatives.

Represented Coach Joe Paterno and his Estate and Family in matters pertaining to the NCAA and Pennsylvania State University.

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Matters

Represented a variety of life science and health care companies, as well as individual employees, officers, consultants and medical professionals, in criminal and civil litigation by multiple U.S. Attorneys Offices, DOJ, HHS-OIG, qui tam Relators, state attorneys general and national Medicaid fraud control units, regarding alleged “off-label” promotion, unlawful inducements and other sales, marketing, pricing and development activities. Successfully represented a variety of clients in these investigations, including prevailing on motions to dismiss False Claims Act lawsuits in federal district court and resolving successfully the largest U.S. False Claims Act matter involving a medical device and kickback allegations.

Represented Janssen Pharmaceuticals, Johnson & Johnson and related companies in a 2013 global resolution of multiple DOJ investigations, including the negotiation and settlement of False Claims Act; Food, Drug & Cosmetic Act; and related allegations. The False Claims Act component of the resolution included seven qui tam complaints venued in the E.D.Pa., D.Mass. and N.D.Ca. Also led the related resolution of administrative claims by HHS-OIG through the company’s Corporate Integrity Agreement. In parallel state litigation, led the resolution of multi-state and individual state consumer protection claims and lawsuits, as well as state claims alleged by Medicaid Fraud Control Units and similar attorneys general and state representatives.

Represented Coach Joe Paterno and his Estate and Family in matters pertaining to the NCAA and Pennsylvania State University.

Represented a Special Committee of independent directors of a major company in criminal and civil accounting-related investigations by a U.S. Attorney’s Office and the SEC.

Represented successfully an officer in a Foreign Corrupt Practices Act criminal investigation; also counseled a major company in FCPA matters in connection with a potential acquisition.

Along with Judge Griffin Bell and King & Spalding partner Wick Sollers, led publicly disclosed internal investigations into the FBI’s Office of Professional Responsibility (OPR) at FBI Director Mueller’s request.

Represented individual targets in an EPA and DOJ RCRA and Clean Water Act grand jury investigation in Montana, resulting in a declination of all criminal charges.

Represented a Fortune 100 company in a DOJ criminal investigation of its environmental practices, resulting in a full declination by the U.S. Attorney’s Office in Maine.

Represented successfully over 20 managerial and sales employees in a federal grand jury investigation in San Francisco regarding Genentech’s marketing and promotional practices.

Counseled bond underwriters, hedge funds and other equity interests regarding a variety of compliance matters involving existing and potential investments.

Represented the Audit Committee of a major publicly traded company in a criminal investigation by DOJ and the U.S. Attorney’s Office in Philadelphia into drug pricing and accounting practices. A favorable civil resolution was obtained from DOJ after a full investigation and negotiations with multiple government agencies.

Represented in Virginia state court a regional manager of a recycling facility accused of health and safety violations, resulting in a full dismissal at trial.

Represented an individual defendant in the then-largest-ever international antitrust conspiracy trial, including authoring a prevailing appellate brief against the New York Times and Dow Jones regarding a First Amendment issue before the Seventh Circuit Court of Appeals in Chicago.

Represented a company in a criminal investigation of alleged illegal seafood importation under the Lacey Act.

Represented multiple companies and individuals in criminal investigations regarding government contracting fraud and tax evasion.

Counseled companies in developing, reviewing or enhancing their corporate compliance programs pursuant to the U.S. Sentencing Commission Guidelines, OIG Guidelines and various industry ethics guidance, such as the PhRMA and AdvaMed Codes.

Advised multiple clients on forensic and electronic discovery matters, including Electronically Stored Information practices, document retention policies, restoration of backup tapes and forensic data mining.

Matters

Represented a variety of life science and health care companies, as well as individual employees, officers, consultants and medical professionals, in criminal and civil litigation by multiple U.S. Attorneys Offices, DOJ, HHS-OIG, qui tam Relators, state attorneys general and national Medicaid fraud control units, regarding alleged “off-label” promotion, unlawful inducements and other sales, marketing, pricing and development activities. Successfully represented a variety of clients in these investigations, including prevailing on motions to dismiss False Claims Act lawsuits in federal district court and resolving successfully the largest U.S. False Claims Act matter involving a medical device and kickback allegations.

Represented Janssen Pharmaceuticals, Johnson & Johnson and related companies in a 2013 global resolution of multiple DOJ investigations, including the negotiation and settlement of False Claims Act; Food, Drug & Cosmetic Act; and related allegations. The False Claims Act component of the resolution included seven qui tam complaints venued in the E.D.Pa., D.Mass. and N.D.Ca. Also led the related resolution of administrative claims by HHS-OIG through the company’s Corporate Integrity Agreement. In parallel state litigation, led the resolution of multi-state and individual state consumer protection claims and lawsuits, as well as state claims alleged by Medicaid Fraud Control Units and similar attorneys general and state representatives.

Represented Coach Joe Paterno and his Estate and Family in matters pertaining to the NCAA and Pennsylvania State University.

See more

Close

Matters

Represented a variety of life science and health care companies, as well as individual employees, officers, consultants and medical professionals, in criminal and civil litigation by multiple U.S. Attorneys Offices, DOJ, HHS-OIG, qui tam Relators, state attorneys general and national Medicaid fraud control units, regarding alleged “off-label” promotion, unlawful inducements and other sales, marketing, pricing and development activities. Successfully represented a variety of clients in these investigations, including prevailing on motions to dismiss False Claims Act lawsuits in federal district court and resolving successfully the largest U.S. False Claims Act matter involving a medical device and kickback allegations.

Represented Janssen Pharmaceuticals, Johnson & Johnson and related companies in a 2013 global resolution of multiple DOJ investigations, including the negotiation and settlement of False Claims Act; Food, Drug & Cosmetic Act; and related allegations. The False Claims Act component of the resolution included seven qui tam complaints venued in the E.D.Pa., D.Mass. and N.D.Ca. Also led the related resolution of administrative claims by HHS-OIG through the company’s Corporate Integrity Agreement. In parallel state litigation, led the resolution of multi-state and individual state consumer protection claims and lawsuits, as well as state claims alleged by Medicaid Fraud Control Units and similar attorneys general and state representatives.

Represented Coach Joe Paterno and his Estate and Family in matters pertaining to the NCAA and Pennsylvania State University.

Represented a Special Committee of independent directors of a major company in criminal and civil accounting-related investigations by a U.S. Attorney’s Office and the SEC.

Represented successfully an officer in a Foreign Corrupt Practices Act criminal investigation; also counseled a major company in FCPA matters in connection with a potential acquisition.

Along with Judge Griffin Bell and King & Spalding partner Wick Sollers, led publicly disclosed internal investigations into the FBI’s Office of Professional Responsibility (OPR) at FBI Director Mueller’s request.

Represented individual targets in an EPA and DOJ RCRA and Clean Water Act grand jury investigation in Montana, resulting in a declination of all criminal charges.

Represented a Fortune 100 company in a DOJ criminal investigation of its environmental practices, resulting in a full declination by the U.S. Attorney’s Office in Maine.

Represented successfully over 20 managerial and sales employees in a federal grand jury investigation in San Francisco regarding Genentech’s marketing and promotional practices.

Counseled bond underwriters, hedge funds and other equity interests regarding a variety of compliance matters involving existing and potential investments.

Represented the Audit Committee of a major publicly traded company in a criminal investigation by DOJ and the U.S. Attorney’s Office in Philadelphia into drug pricing and accounting practices. A favorable civil resolution was obtained from DOJ after a full investigation and negotiations with multiple government agencies.

Represented in Virginia state court a regional manager of a recycling facility accused of health and safety violations, resulting in a full dismissal at trial.

Represented an individual defendant in the then-largest-ever international antitrust conspiracy trial, including authoring a prevailing appellate brief against the New York Times and Dow Jones regarding a First Amendment issue before the Seventh Circuit Court of Appeals in Chicago.

Represented a company in a criminal investigation of alleged illegal seafood importation under the Lacey Act.

Represented multiple companies and individuals in criminal investigations regarding government contracting fraud and tax evasion.

Counseled companies in developing, reviewing or enhancing their corporate compliance programs pursuant to the U.S. Sentencing Commission Guidelines, OIG Guidelines and various industry ethics guidance, such as the PhRMA and AdvaMed Codes.

Advised multiple clients on forensic and electronic discovery matters, including Electronically Stored Information practices, document retention policies, restoration of backup tapes and forensic data mining.

Credentials

J.D., Harvard University, cum laude

B.A., Indiana University, summa cum laude, Phi Beta Kappa

District of Columbia

U.S. Court of Appeals for the Seventh Circuit

U.S. District Court for the Northern District of Illinois

U.S. District Court for the Southern District of Indiana

Law Clerk, Hon. Sarah Evans Barker, U.S. District Court for the Southern District of Indiana

"Mark is the best in the business. The combination of experience, education and demeanor is outstanding."


2024 Client Feedback to Ranking Guide

"I thank him and his team every day. I can't say anything stronger than that."


2024 Client Feedback to Ranking Guide

"few firms that can match the experience or success rate that Mark and the K&S team bring...the first call we make."


2024 Client Feedback to Ranking Guide

Litigation Star: White Collar and Civil Litigation


BENCHMARK LITIGATION (2023 and previous editions)

One of six lawyers nationwide shortlisted for Government Investigations Attorney of the Year


LMG Life Sciences (2023 & 2022)

White-Collar Criminal Defense, Leading Lawyer


Legal 500 U.S. (2024 and previous editions)

LMG Life Sciences Star: White Collar/Government Investigations


LMG Life Sciences (2023 and previous editions)

What Clients Say: “Mark has an ingrained understanding of the practical approach we favor.” “He knows what to fight for."


BTI Consulting Group (2020)

BTI Client Service All-Star


BTI Consulting Group (2020)

“Quickly Made a Name for Himself as an Extremely Accomplished Lawyer”...“An Excellent Track Record”...“Creative”


Legal 500 U.S. (2011)

“One of Five U.S. White-Collar Lawyers to Watch”


Law360 (2011)

“One of the Most Sought-After Corporate Defenders in the Country”


Law360 (2011)

Close

Recognition

"Mark is the best in the business. The combination of experience, education and demeanor is outstanding."


2024 Client Feedback to Ranking Guide

"I thank him and his team every day. I can't say anything stronger than that."


2024 Client Feedback to Ranking Guide

"few firms that can match the experience or success rate that Mark and the K&S team bring...the first call we make."


2024 Client Feedback to Ranking Guide

Litigation Star: White Collar and Civil Litigation


BENCHMARK LITIGATION (2023 and previous editions)

One of six lawyers nationwide shortlisted for Government Investigations Attorney of the Year


LMG Life Sciences (2023 & 2022)

White-Collar Criminal Defense, Leading Lawyer


Legal 500 U.S. (2024 and previous editions)

LMG Life Sciences Star: White Collar/Government Investigations


LMG Life Sciences (2023 and previous editions)

What Clients Say: “Mark has an ingrained understanding of the practical approach we favor.” “He knows what to fight for."


BTI Consulting Group (2020)

BTI Client Service All-Star


BTI Consulting Group (2020)

“Quickly Made a Name for Himself as an Extremely Accomplished Lawyer”...“An Excellent Track Record”...“Creative”


Legal 500 U.S. (2011)

“One of Five U.S. White-Collar Lawyers to Watch”


Law360 (2011)

“One of the Most Sought-After Corporate Defenders in the Country”


Law360 (2011)