In my opinion, it would be:
Isaac Newton
Here's why:
Sir Isaac Newton (Jan. 4, 1643–March 31, 1727) was a superstar of physics, math, and astronomy even in his own time. He occupied the chair of Lucasian Professor of Mathematics at the University of Cambridge in England, the same role later filled, centuries later, by Stephen Hawking. Newton conceived of several laws of motion, influential mathematical principels which, to this day, scientists use to explain how the universe works. Therefore, he would be a great person to write a biography on.
I hope this answer helps you out! Have an amazing day and have fun writing your biography. Good luck :)