Leon Sacks was born in Philadelphia, Pennsylvania. He graduated from the Wharton School of the University of Pennsylvania at Philadelphia in 1923, and from the law department of the University of Pennsylvania in 1926. He commenced the practice of law in Philadelphia in 1926. He was appointed deputy Attorney General of Pennsylvania in February 1935 and served until January 1937. He was elected as a member of the Democratic State committee in 1936 and served until 1942.
He served at Army Air ForcesEastern Flying Training Command, with the rank of lieutenant colonel, from January 4, 1943, to January 10, 1946, when resumed the practice of his profession. He was a member of State Veterans Commission from 1951 to 1969, and the chairman of the registration commission of Philadelphia from 1952 to 1965. He was a member of Military Reservations Commission from 1957 to 1967.