Leachman is best known as Phyllis Lindstrom, the character she played on The Mary Tyler Moore Show from 1970 to 1975, and in her own spin-off, Phyllis, from 1975 to 1977. She also played Frau Blücher in the 1974 Mel Brooks' film Young Frankenstein. She co-starred in the Wonder Woman television series and the 2005 film Sky High with Muppet Show guest star Lynda Carter.
Leachman was a contestant on Dancing with the Stars' seventh season. On the season nine finale in 2009, Miss Piggy interviewed Leachman, who was making a guest appearance. During the interview, Leachman joked about avoiding Miss Piggy, for fear of getting the "swine flu".