Dennis Duncan

Dennis Duncan is a Sioux Falls attorney whose practice includes health care law, business law, insurance, civil litigation, administrative law, corporate matters, and legislative lobbying. Dennis has practiced in South Dakota since the 1970s and has represented clients on legal and regulatory issues that often involve businesses, health-care organizations, insurers, and government processes. His work combines advisory, litigation, and public-policy experience across closely related practice areas.

Dennis earned a B.A. from the University of South Dakota in 1970 and a J.D. from the University of South Dakota in 1973. His legal education led to a clerkship with Justice Frances Dunn of the South Dakota Supreme Court early in his career. That combination of undergraduate study, law school, and judicial experience established a foundation for legal research, litigation, regulatory work, and long-term counseling of institutional clients.

Dennis spent decades in private practice handling health care, insurance, business, and administrative matters and has been associated with professional organizations addressing health law, defense practice, and legislative advocacy. His work has included civil litigation and regulatory counseling as well as lobbying and government-relations issues. He has also been admitted in South Dakota and federal court, giving him experience across both state and federal legal forums.

Dennis Duncan has built a long South Dakota practice around legal issues that sit at the intersection of regulated industries, business operations, insurance, and government action. Dennis’s background in litigation and health-related organizations supports a practical understanding of how legal rules affect institutions and professionals. He helps clients evaluate regulatory obligations, business concerns, disputed matters, and policy issues with the perspective of many years in practice.

Law Office Affiliations

• Attorney, The Duncan Law Firm, LLP
• State Bar Commissioner, State Bar of South Dakota (2017-Present)
• Director, University of South Dakota Law School Foundation
• Member, American Bar Association
• Member, South Dakota Defense Lawyers Association
• Member, National Health Lawyers Association
• Member, Forum Committee on Health Law – American Bar Association
• Member, American League of Lobbyists
• Member, Defense Research Institute, Inc.
• Member, Litigation Counsel of America
• Member, Group Health Association of America
• Member, American Medical Association’s Doctors Advisory Network

Licensed State

• South Dakota

Education

• University of South Dakota
  Juris Doctor (JD)
• University of South Dakota
  Bachelor of Arts (BA) in Government

Awards & Badges