At Fox he made a musical, "Something for the Boys" (1944), with Carmen Miranda. O'Shea then went into "It's a Pleasure!" (1945), playing a hockey star who marries figure skater Sonja Henie, done for International Pictures. Back at Fox he had the lead in a B, "Circumstantial Evidence" (1945). O'Shea returned to Broadway with a role in the revival of "The Red Mill" (1945–47), produced by Hunt Stromberg Jr. which ran for 531 performances. When the show finished he returned to films. He had a support part with "Mr. District Attorney" (1947) at Columbia. He was Nancy Coleman's leading man in "Violence" (1947) at Monogram Pictures and played Natty Bumpo in Sam Katzman's version of "Last of the Mohicans", "Last of the Redmen" (1947), with Jon Hall at Columbia. He had a support role in "Smart Woman" (1948), at Allied Artists, and the lead in "Parole, Inc." (1949), for Eagle-Lion Films. He supported Mickey Rooney in "The Big Wheel" (1949) at United Artists but had the lead in "The Threat" (1949) a "B" for RKO. O'Shea supported John Payne in "Captain China" (1950) and Dan Duryea in "The Underworld Story" (1950). He had a support role in "Disc Jockey" (1951), then did three films at Fox: "Fixed Bayonets" (1951) for Sam Fuller, "The Model and the Marriage Broker" (1951) for George Cukor, and "Bloodhounds of Broadway" (1952). After his career in film waned - he was largely out of films by 1952 — he took many roles in television. He acted in TV programs such as "The Revlon Mirror Theater", "Ethel Barrymore Theatre", "Damon Runyon Theater", and "Schlitz Playhouse of Stars". He had a support part in "It Should Happen to You" (1954). He also starred in the NBC sitcom "It's a Great Life" from 1954-1956 as Denny Davis, a former GI trying to find a civilian job. Frances Bavier played his landlady. He won an Emmy in 1954 but quit the show in 1957.