But his career didn't really take off until he returned from serving as a Marine in World War II, first earning an Oscar nomination for his portrayal of an anti-Semitic killer in Crossfire (1947), then playing an aging boxer in The Set-Up (1949) and a conflicted cop in On Dangerous Ground (1952).
The 1960s found Ryan appearing in a string of all-star war films, including The Longest Day (1962), Battle of the Bulge (1965) and The Dirty Dozen (1967), as well as classic Westerns such as Richard Brooks's The Professionals (1966) and Sam Peckinpah's The Wild Bunch (1969). He died on July 11, 1973, at the age of 63.