He appeared in many classic films from the 1930s through the 1960s, including his role as General Martin Peterson on the 1960s NBC television comedy series I Dream of Jeannie, with Barbara Eden and Larry Hagman.

The success of Rendezvous landed MacLane a contract with Warner Bros. and brought him to the attention of several renowned film directors, including Fritz Lang, Michael Curtiz, and William Keighley.

As a result, throughout the remainder of the 1930s, MacLane was highly active in film, with major supporting roles in such productions as The Case of the Curious Bride, G Men, The Prince and the Pauper, and Lang's You Only Live Once and You and Me.

He also played the role of detective Steve McBride, opposite Glenda Farrell in seven of the nine films featuring the fictional newspaper reporter Torchy Blane.

He played Lieutenant Dundy, who interacted with Bogart's Sam Spade in The Maltese Falcon, writer/director John Huston's acclaimed film noir based upon Dashiell Hammett's novel.

MacLane's many other film credits during the 1940s include The Big Street, Victor Fleming's Dr. Jekyll and Mr Hyde, Fritz Lang's Western Union, Reginald Le Borg's The Mummy's Ghost, and Frank Borzage's The Spanish Main.

During the 1960–1961 television season, MacLane was a series regular on twenty-seven episodes of NBC's western, Outlaws, in which he played Marshal Frank Caine.

[3] MacLane died of double pneumonia on New Year's Day, at Saint John's Health Center in Santa Monica, California, a week after his 66th birthday.