1953–1962: MGM and leading roles
MGM was impressed by Tamblyn's performance in Retreat, Hell! and signed him to a long-term contract. He called this "the second big break" of his career.
Tamblyn's first role under the contract was as a young soldier in boot camp in Take the High Ground! (1953), directed by Richard Brooks. His training as a gymnast and abilities as an acrobat prepared him for his breakout role as Gideon, the youngest brother, in Seven Brides for Seven Brothers (1954). Tamblyn has said the director wanted to cast a Broadway dancer but MGM insisted the filmmakers use some contract talent, so he and Jeff Richards were cast.
Tamblyn was not a trained dancer and always considered himself an actor who danced rather than the other way around, but the film was a big success and established him at MGM. He has said his career "really took off" after the film.
Tamblyn was one of many studio contract players in the musical Deep in My Heart (1954). He played Eleanor Parker's brother in the Western Many Rivers to Cross (1955) and was one of several young MGM actors (including Jane Powell and Debbie Reynolds) in the musical Hit the Deck (1955).
Tamblyn supported older actors in two Westerns: Robert Taylor and Stewart Granger in The Last Hunt (1956), a flop; and Glenn Ford and Broderick Crawford in The Fastest Gun Alive (1956), a big hit in which he performed an extraordinary "shovel" dance at a hoedown. He served (uncredited) as a choreographer for Elvis Presley in 1957's Jailhouse Rock. MGM loaned Tamblyn to Allied Artists for his first star role, The Young Guns (1957). Back at MGM, he supported Glenn Ford and Gia Scala in Don't Go Near the Water (1957), a comedy set among members of the U.S. Navy.
20th Century Fox borrowed Tamblyn to play Norman Page in Peyton Place (1957) opposite Lana Turner and Diane Varsi, a performance for which he was nominated for an Academy Award for Best Supporting Actor. Tamblyn then went to England to play the title role in the musical Tom Thumb (1958), made for George Pal. When he returned, MGM cast him as the lead in High School Confidential (1958), a solid hit.
Tamblyn's career momentum was interrupted when he was drafted into the United States Army in 1958. During his service he was given leave to play a prominent supporting part in Cimarron (1960).
Tamblyn's best-known musical role is as Riff, the leader of the Jets street gang in West Side Story (1961). He then appeared in two MGM Cinerama movies, The Wonderful World of the Brothers Grimm, again for Pal, and How the West Was Won (both 1962).
Tamblyn played Luke Sannerson in The Haunting (1963) for Robert Wise, who had made West Side Story. Tamblyn said he originally turned down the role as he disliked the part but agreed to do it when MGM threatened to put him on suspension. He then played "Smitty" Smith in MGM's Follow the Boys (also 1963).