B movies, television, and Broadway
Montalbán did a swashbuckler for Sam Katzman, The Saracen Blade (1954), then returned to Mexico to star in Untouched (1954).
He travelled to Italy to make The Queen of Babylon (1954) with Rhonda Fleming, then returned to Mexico to make the US-financed A Life in the Balance (1955) with Anne Bancroft. He bought a story for himself, Green Shadows, but it appears not to have been made.
Montalbán began working in television, guest-starring on shows such as General Electric Theater, The Ford Television Theatre, Celebrity Playhouse, Climax!, The 20th Century-Fox Hour (versions of Broken Arrow and Five Fingers), Chevron Hall of Stars, Wagon Train, and Schlitz Playhouse.
In 1955, he appeared on Broadway with Gloria DeHaven in a musical adaptation of Seventh Heaven, but it ran for only forty-four performances. In Hollywood, he appeared in the thriller for Allied Artists, Three for Jamie Dawn (1956).
Montalbán returned to Italy for Desert Warrior (1957), then had his first role in an "A" Hollywood film for a number of years in Sayonara (1957), in which he played a Japanese dancer. He later said, "I was and still am very pleased with my performance and very much saddened by this picture. I was hoping for an Academy Award nomination, but unfortunately, most of my scenes ended up on the cutting-room floor."
From 1957 to 1959, Montalbán starred in the Broadway musical Jamaica, singing several light-hearted calypso numbers opposite Lena Horne, which ran for 558 performances. His performance earned him a Tony Award nomination.
Montalbán continued to guest-star on shows such as Colgate Theatre and Playhouse 90. When Jamaica ended, he guest-starred in Riverboat, Adventures in Paradise, Startime, Death Valley Days, Bonanza, Alfred Hitchcock Presents, The Christophers, The Dinah Shore Chevy Show, The Loretta Young Show (several times), Zorro, The Untouchables, Checkmate, Cain's Hundred, and The Lloyd Bridges Show.
Montalbán could also be seen in Let No Man Write My Epitaph (1960); the TV remake of Rashomon (1960) directed by Sidney Lumet; Rage of the Buccaneers (1961), an Italian swashbuckler in which Montalbán had a lead role alongside Vincent Price; Hemingway's Adventures of a Young Man (1962); The Reluctant Saint (1963) with Maximillian Schell; and Love is a Ball (1963) with Glenn Ford, playing a French duke. He was the Native American leader Little Wolf in Cheyenne Autumn (1964) directed by John Ford, did the TV version of The Fantasticks (1964), and returned to Mexico to make ¡Buenas noches, año nuevo! (1964).
He was mostly seen, though, on television in Alcoa Premiere, The Dick Powell Theatre, Ben Casey, The Greatest Show on Earth, The Lieutenant, The Great Adventure, Slattery's People, The Defenders, The Rogues, Burke's Law, Dr. Kildare, and The Man from U.N.C.L.E.
Montalbán had supporting roles in The Money Trap (1965) with Ford, directed by Burt Kennedy, Madame X (1966) with Turner for producer Ross Hunter, and The Singing Nun (1966) with Debbie Reynolds at MGM.
He guest-starred in The Long, Hot Summer, Daniel Boone, The Wild Wild West, Insight, Combat!, Mission: Impossible, I Spy, Hawaii Five-O (playing a Japanese-American crime boss ), and Bob Hope Presents the Chrysler Theatre.
In 1965, he toured in The King and I. "'I think every actor loves the stage,' he said in 1991. 'The pros are that it is the actor's medium; there's no way your scene is going to end up on the cutting-room floor, and it's up to you to get and keep the attention of the audience by the truth of your performance.'"
He appeared in the television films Alice Through the Looking Glass (1966) (for which his fee was $10,000, equivalent to $99,000 today.) and Code Name: Heraclitus (1967), and the features The Longest Hundred Miles (1967), Sol Madrid (1968), and Blue (1968). He also guest-starred on "Space Seed", an episode of Star Trek. "I'm like a doctor on 24-hour call," he said in a 1967 interview. "I don't turn anything down."
Montalbán also starred in radio, such as on the internationally syndicated program Lobo del Mar (Seawolf), in which he was cast as the captain of a vessel that became part of some adventure at each port it visited. This 30-minute weekly show aired in many Spanish-speaking countries until the early 1970s.