David Bailey does a good job of summarising Simons remarkable career.
Simons’ background hardly suggested that he would one day lead one of the most successful, if not the most successful, quantitative hedge fund operation in the world.
Born in 1938 to a Jewish family that operated a small shoe factory, Simons aspired very early to be a mathematician, ultimately receiving a B.S. degree from the Massachusetts Institute of Technology at the age of 20, and a Ph.D. from the University of California, Berkeley at the age of 23. His doctoral thesis presented a new proof of Berger’s classification of the holonomy groups of Riemannian manifolds. Later, in collaboration with Shing-Shen Chern, he discovered and proved what is now known as the Chern-Simons theorem (and associated theory), which deals with 3-dimensional quantum field theory and also has applications in string theory and quantum computing. For this and some related work, in 1976 he received the Oswald Veblen Prize in Geometry.
More here – Mathematical Investor