Born Samuel Lawrence Klausman Parks in Olathe, Kansas, his career was virtually ended when he admitted in 1951 to having been a member of a Communist party cell.

Parks grew up in Joliet, Illinois, and graduated from Joliet Township High School in 1932. Having attended the University of Illinois as a pre-med student, Parks played in stock companies for several years before signing a Hollywood contract in 1941. He made several forgettable films until he won the role of Al Jolson in the 1946 biographical film The Jolson Story, for which he was nominated for an Academy Award for Best Actor.

Following his Oscar nomination, he made a few more movies that did little in the box office, until he appeared in the sequel, Jolson Sings Again in 1949, which was another hit.

Larry Parks was summoned to appear before the House Un-American Activities Committee where he literally fell on his knees before and begged not to be forced to testify. He eventually did so in tears, only to find that he was blacklisted anyway. Following his admission before the Congressional Committee, Columbia Pictures dropped him. He made only two more films, but continued to eke out a living acting on the stage and doing occasional television programs until his death, from a heart attack, aged 60. Married to actress Betty Garrett from 1944 until his death; they had two sons.