She is best known for her role as Katie Kanisky on the NBC sitcom Gimme a Break!
She sang on the soundtrack for Sesame Street and was performing in Off-Broadway plays by age 11.
In 1975, her family moved to Beverly Hills, and Michaelsen (who changed her name from Markussen) soon won guest spots on such shows as Diff'rent Strokes and Eight Is Enough.
[1] She graduated from Beverly Hills High School in 1979 and studied at University of California, Los Angeles.
[3] Michaelsen is longtime friends with retired actress Kristy McNichol.