Olmsted's appearances during the era of live television began in 1950 with The Chevrolet Tele-Theatre and Lights Out, followed by Schlitz Playhouse of Stars (1951). The Philco Television Playhouse (1951–52), Kraft Television Theatre (1951–52), Tales of Tomorrow (1952), Hallmark Hall of Fame (1952), Goodyear Television Playhouse (1953), Robert Montgomery Presents (1953–54), Studio One (1954–55), The Phil Silvers Show (1955-59) and NBC Sunday

 Showcase (1959).Nelson Olmsted narrated and acted in over 150 episodes of the Ohio Story television series. Image courtesy of Hagley Museum and LibraryOlmsted (facing camera) was a popular actor in the early days of television. Image courtesy of Hagley Museum and LibraryIn October 1952, Olmsted replaced Robert Waldrop as the narrator and star of the regional Ohio Story radio and television series. The series, sponsored by Ohio Bell, written by Frank Siedel and produced by Stuart Buchanan, ran for 15 years. At the time the series was the longest-running regional scripted program in the nation.

When the series came to an end in 1961, 1,309 radio and 175 television episodes had been produced. Olmsted narrated and starred in almost all of the television episodes and approximately 300 of the radio episodes. Ray Culley of Cinécraft Productions directed the television episodes.

Olmsted made guest appearances on the CBS court drama series Perry Mason, including the role of murderer Arthur Colemar in the 1960 episode, "The Case of the Treacherous Toupee." He guest-starred in the Fess Parker Daniel Boone series, Season 5 episode 19 as Thaddeus King from Bourbon County, Kentucky. He also guest-starred in a 1961 episode, "A Doctor Comes to Town," of the series Window on Main Street. He continued in television until the mid-1970s.His film roles included Middle of the Night (1959), That Touch of Mink (1962), Diary of a Madman (1963), Fitzwilly (1967) and Butch Cassidy and the Sundance Kid (1969). His last movie was Hughes and Harlow: Angels in Hell (1977)