American leading man of suave or sinister roles, a collateral relative of George Washington and William Barclay "Bat" Masterson, Scott was the son of a wealthy surgeon. Intending to follow in his father's footsteps, Scott studied at the University of Texas, but his true passion lay in the theater. He dropped out of college and signed on as a cabin boy on a freighter bound for England, where he found work in provincial repertory, gaining confidence and skill.
Returning to Texas, Scott married actress Elaine Anderson and became active in local theater in Austin. His talents were soon spotted by Alfred Lunt, who recommended him to the producers of New York's Theatre Guild. This led to a successful entry into the Broadway stage, with appearances in several successes. He was noticed by Jack L. Warner, who signed him to a film contract and introduced him to film audiences in the title role of The Mask of Dimitrios (1944).
Scott's performance as the mysterious and debonair scoundrel was well-received, and he seemed destined for a top-level career in movies. Jean Renoir next cast him in a touching and sensitive role in his classic The Southerner (1945). Although he received great acclaim for his performance, Scott was not particularly well-promoted by Warners. His profile was immediately reversed by his well-received performance as the cad in Mildred Pierce (1945),which seemed likely to cement him as a star.
However, this role also led to his typecasting as a portrayer of amoral characters, and his subsequent films declined in prestige. In 1950, a divorce and a rafting accident, in which he was badly injured, sent him into a depression. He subsequently married actress Ruth Ford and began to concentrate more on stage and television work. Although he continued to work in films, including one for director Luis Buñuel, Scott never quite reclaimed the level of stardom that he'd achieved in the mid-1940s.
In 1965, Scott was stricken with a brain tumor. Despite surgery, he succumbed in October of that year, at the age of 51. He was buried in Austin, Texas.