Was spotted by Bob Hope in a 1975 fashion show and asked to join his troupe of entertainers on a tour of veterans hospitals and military bases.
Was Penthouse Pet of the Month under the name Joann Witty in the March 1976 issue. The magazine sought to republish the photos under her real name in 1983 after she became a regular on the sitcom Three's Company and she sued.
In 1981, replaced Jenilee Harrison (who had replaced Suzanne Somers) in Three's Company.
Was considered for the role of Willie Scott in Steven Spielberg's Indiana Jones and the Temple of Doom (1984), but could not accept due to shooting conflicts with her sitcom.
Portrayed Hildy Granger on the 1987 pilot of the sitcom She's the Sheriff, a part that was subsequently played in the series by Suzanne Somers.
Has toured and made public appearances with her Three's Company costars Joyce DeWitt and Richard Kline.