By 1944, he was in a United States Army Air Forces basic training camp in Wichita Falls, Texas, and served until 1945. Both of his parents became naturalized United States citizens in 1941. He attended Horace Mann School and earned a BA, MA, and PhD in Comparative Literature at Harvard University. As a student, Simon was hired by playwright Lillian Hellman to prepare a translation of Jean Anouilh's "The Lark", but he was reportedly only paid $50, half of the agreed amount, because, in his own words, he gave her fifty double-spaced pages but she had expected that many pages in single-space.