Dorothy Martin was born on 18 September 1919 in Bacon Township, Vernon County, Missouri to Laudell M (née Flynn) (1892–1978) and Robert W. Martin.
She received her AB degree from Southwest Missouri State University where her father was head of the science department. There, she was the first graduate to achieve a perfect score (4.0 GPA). From there, she attended the University of Chicago for one year, before transferring to University of Illinois to become an assistant to a professor. She earned her PhD in physical chemistry in 1945 from the University of Illinois, with thesis work regarding radon. She married Sidney Simon, a fellow graduate student from the University of Chicago, in 1946 and took his surname.