Retzinger is a Chambers USA ranked healthcare litigator who represents providers, physician organizations, hospitals, health systems, healthcare technology companies and other healthcare stakeholders in complex litigation, government investigations, regulatory enforcement matters and related advisory work. His practice focuses on high-stakes healthcare reimbursement and managed care disputes, the No Surprises Act, and the False Claims Act.

“Jonah’s impressive national practice is a valuable addition to our healthcare platform and advances our continued investment in healthcare litigation, particularly in complex reimbursement disputes, provider-side healthcare litigation, False Claims Act matters, and healthcare regulatory enforcement,” said Mark Polston, leader of King & Spalding's Healthcare team. “His experience at the intersection of healthcare litigation and regulation, combined with his entrepreneurial approach to identifying emerging market opportunities, aligns exceptionally well with our ability to serve providers navigating an increasingly challenging reimbursement and enforcement landscape.”

Retzinger joins King & Spalding from Nixon Peabody, where he was a partner. He earned his J.D. from Duke University School of Law and his B.B.A. from the College of William & Mary.

“King & Spalding offers a premier platform for growing my provider-focused healthcare litigation and investigations practice,” said Retzinger. “The firm’s deep relationships across the healthcare industry, its outstanding litigation and regulatory capabilities, and its collaborative culture create tremendous opportunities to serve clients facing increasingly complex reimbursement, enforcement and compliance challenges.”

King & Spalding’s healthcare team has added a total of nine partners since the summer of 2025, including Retzinger. Earlier this month, healthcare regulatory and investigations partner Troy Barsky joined the firm. In January, King & Spalding welcomed a five-partner Medicaid financing and managed care litigation team, which includes Rachel Gilbert, Cat Kirkland, Jim Gilliam and John Connell, and Renee Rayne. David Hoskins, former lead litigation counsel for the Centers for Medicare & Medicaid Services, joined in August 2025 and Rob DeConti, former Chief Counsel for the Department of Health and Human Services Office of Inspector General, joined in June 2025.