After recieving a doctorate in mathematics at the University of Uppsala in Sweden (and longdistant study under MittagLeffler), I worked as an actuary for 8 years.
In 1906, I was appointed Professor of Theoretical Physics at Stockholm, where I began my work on theoretical mathematics.
My primary mathematical contribution was being the "father" of the modern theory of integral equations and work in spectral theory.
Basically I overcame previous unsuccessful efforts on solving integral equations (especially by Vito Volterra) by treating each equation as a limiting form of a system of linear algebraic equations with the number of unknowns becoming infinitely large.
Another strong interest was music, especially playing and studying the violin (Bach rules!)...in fact I built my first violin from half a coconut.
For my mathematical successes, I was awarded the Wallmark prize of the Swedish Academy and the Poncelet prize by the French Academy.
Answer:
Eric Ivar Fredholm (1866  1927)
