Winters was born Jonathan Harshman Winters III in Dayton, Ohio on November 11, 1925. He is of Irish-Scottish-English descent. During his senior year at Springfield High School, Winters quit school to join the United States Marine Corps and served two and a half years in the Pacific Theater during World War II. After his return, he attended Kenyon College. He later studied cartooning at Dayton Art Institute, where he met Eileen Schauder, whom he married on September 11, 1948. He was a brother of the Delta Kappa Epsilon fraternity (Lambda chapter).