UnitedHealth Group Incorporated
Leadership History
4 leaders · 1991 to present
Stephen J. Hemsley is the CEO of UnitedHealth, in the role since 2025. The first chief executive was William W. McGuire, from 1991.
| Name | Role | From | To | Years in role |
|---|---|---|---|---|
| Stephen J. Hemsley | Chair and Chief Executive Officer | 2025 | Present | 1 |
| Tim Noel | Chief Executive Officer, UnitedHealthcare | 2025 | Present | 1 |
| Andrew Witty | Chief Executive Officer (Former) | 2021 | 2025 | 4 |
| William W. McGuire | Chairman and Chief Executive Officer | 1991 | 2006 | 15 |
UnitedHealth is best understood as a healthcare operating system: insurance premiums and claims create scale, Optum manages pharmacy and care services, and data flows help price risk, coordinate care, and manage cost. The company is headquartered in Minnetonka, Minnesota.
UnitedHealth makes money in two connected ways. UnitedHealthcare collects premiums from employers, individuals and government programs (Medicare Advantage and Medicaid) and earns fees for administering self-funded employer plans; profit depends on keeping medical costs below premiums. Optum sells services: Optum Rx runs pharmacy benefit management and specialty pharmacy, Optum Health delivers primary, specialty and home care (often under value-based contracts that pay a fixed amount per patient), and Optum Insight sells data, analytics, claims and revenue-cycle technology. Optum serves UnitedHealthcare and outside payers, so some dollars UnitedHealthcare pays out return as Optum revenue. Premiums from CMS programs made up 44% of 2025 consolidated revenue.
Chair and Chief Executive Officer
2025 – Present
1 year (current)
Returned as CEO in May 2025 after serving as CEO from 2006 to 2017 and then as board chair. Prioritized Medicare Advantage repricing, benefit redesign, membership right-sizing and an Optum Health reset.
Under his second term, quarterly net margin recovered to 4.9% in Q2 2026 and 2026 adjusted EPS guidance was raised to $19.50-$20.00.
Chief Executive Officer, UnitedHealthcare
2025 – Present
1 year (current)
Took over UnitedHealthcare after the December 2024 killing of Brian Thompson and has led benefit and pricing changes in Medicare Advantage.
Remains UnitedHealthcare CEO after Robert Hunter was named UnitedHealthcare president in September 2026.
Chief Executive Officer (Former)
2021 – 2025
4 years
Led UnitedHealth from February 2021, expanded Optum Health through deals including LHC Group and Amedisys, and managed the response to the February 2024 Change Healthcare ransomware attack, including congressional testimony.
Oversaw revenue growth past $400 billion but stepped down in May 2025, citing personal reasons, as medical costs surged and the company suspended its 2025 guidance.
Chairman and Chief Executive Officer
1991 – 2006
15 years
McGuire became chief executive in 1991 and built United HealthCare into the largest US health insurer through acquisitions.
He left in 2006 after an investigation into the backdating of stock options. Stephen Hemsley succeeded him.
UnitedHealth faces elevated medical cost trends, Medicare Advantage rate and risk-adjustment pressure, DOJ criminal and civil investigations into its Medicare business, PBM reform, shareholder litigation over 2024-2025 disclosures, cybersecurity risk after the 2024 Change Healthcare attack, and the need to restore Optum Health margins.
Key leaders include founder Richard T. Burke (1977–1988), Kennett Simmons (1988–1991), Dr. William W. McGuire (1991–2006), Stephen J. Hemsley (2006–2017), David S. Wichmann (2017–2021), and Sir Andrew Witty (February 2021–present).
A former pulmonologist, Dr. McGuire engineered UnitedHealth's rise into a national juggernaut through dozens of mergers, pioneering software-driven claims management and taking market cap from $500 million to over $60 billion.
McGuire resigned in October 2006 following an internal legal review that uncovered extensive backdating of employee stock option grants, which had artificially inflated option values over a 15-year period.
A former Arthur Andersen managing partner, Stephen Hemsley restored corporate integrity, weathered the 2010 ACA reforms, conceptualized and created Optum in 2011, and oversaw a tenfold increase in company revenues before transitioning to Chairman of the Board.
A veteran financial leader at the firm, David Wichmann focused on global expansion, technology adoption, and navigating the onset of the COVID-19 pandemic before retiring in early 2021.
Sir Andrew Witty served as Chief Executive Officer of global pharmaceutical giant GlaxoSmithKline (GSK) from 2008 to 2017, later joined UnitedHealth as CEO of Optum in 2018, and took a temporary leave in 2020 to co-lead the World Health Organization's COVID-19 vaccine program.
Witty led the defense of the $13 billion Change Healthcare acquisition against the DOJ, managed the aftermath of the catastrophic February 2024 ransomware cyberattack, and guided the company through heightened regulatory scrutiny of Medicare Advantage.
Brian Thompson served as CEO of insurance subsidiary UnitedHealthcare from April 2021 until his tragic murder in December 2024, leading commercial, Medicare, and Medicaid benefits programs with operational excellence.
As Executive Chairman of the Board, Stephen Hemsley works closely with Andrew Witty and the board of directors, providing long-term strategic guidance on capital allocation, enterprise risk, and executive succession.
Executive compensation is heavily weighted toward long-term equity performance shares tied to multi-year compound growth in adjusted EPS, revenue growth, and Return on Invested Capital (ROIC).
CEO Andrew Witty has testified before both House and Senate committees regarding cybersecurity defenses following the Change Healthcare breach, PBM transparency, and Medicare Advantage risk scoring practices.
A philosophy centered on holistic clinical integration—using Optum's clinical scale and data science to simplify healthcare, eliminate administrative friction, and deliver compassionate preventive care.
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