Though born in Arkansas, I moved a lot (Illinois, Michigan, California) because my father was a professor of accounting who changed teaching positions.
While getting an undergraduate degree at Cal Tech, I also passed the first four actuary exams and worked as a parttime actuary to put myself through school.
Though I received my Ph.D. fro the University of Wisconsin, I returned to Cal Tech to be a mathematics professor there (Editorial NOTE: He was a professor there during my Cal Tech stint...I knew him but did not have any classes from him.)
My original math research involved combinatorial geometries which led into grouptheory...and here I had gotten a grade of C when I had taken abstract algebra at Cal Tech.
Somehow. I was able to publish research results involving finite groups at a very fast rate, to the extent that "many other mathematicians decided to leave the field to pursue other problems."
In fact, I became one of the primary investigators in the completion of the classification of finite simple groups in the 1970s and 1980s...inlcuding my final correction with Stephen Smith in 2004.
Mathematicians view my proofs as very difficult to read, seemingly lacking explanations of very sophisticated or complex counting arguments.
I have been fortunate to receive many awards: the Cole Prize, election to both the National Academy of Sciences and the American Academy of Arts and Sciences, the Rolf Schock Prize for Mathematics by the Royal Swedish Academy of Sciences, the Leroy P. Steele Prize for Mathematical Exposition, and the Wolf Prize in Mathematics.
Answer:
Michael Aschbacher (1944  )
