Kenneth A. Ribet studied mathematics at Brown University and Harvard University. He received his PhD in 1973 from Harvard, where his advisor was John Tate. After three years of teaching in Princeton and two years of research in Paris, Ribet joined the University of California, Berkeley faculty in 1978.
Ribet is known for his work in number theory and algebraic geometry. He played a prominent role in the proof of Fermat's Last Theorem by showing that this statement was a logical consequence of a conjecture about elliptic curves. (Andrew Wiles proved this conjecture in 1995, thereby obtaining Fermat's Last Theorem as a corollary.)
Ribet was elected to the American Academy of Arts and Sciences in 1997 and the National Academy of Sciences in 2000. He was awarded the Fermat Prize in 1989 and received an honorary PhD from Brown University in 1998. Ribet was inducted as a Vigneron d'honneur by the Jurade de Saint Emilion in 1988.