Founder Profile
Leonard S. Schleifer
Last reviewed: October 2026 · By Swet Parvadiya
Who is Leonard S. Schleifer?
Leonard S. Schleifer is a founder of Regeneron Pharmaceuticals, Inc., which was founded in 1988 with George D. Yancopoulos.
- Company founded
- Regeneron Pharmaceuticals, Inc.
- Founded
- 1988
- Co-founders
- George D. Yancopoulos
Background
M.D. and Ph.D. from the University of Virginia; trained in neurology at Cornell University Medical College, where he was an assistant professor before founding Regeneron.
Founding Story
Leonard S. Schleifer founded Regeneron in 1988 and has led it as CEO since then, making him one of the longest-serving founder-CEOs in the S&P 500. He is also President and Board co-Chair. He guided the company through early clinical failures, its 1991 IPO, and its growth into a $14 billion-revenue biotech.