Best known for portraying Frenchy in Grease and Grease 2, she also played Helen on the television series The Practice. In the 2016, Fox aired Grease Live!, in which Conn played the role of Vi. She became a contestant on Dancing on Ice in 2019.
In 1962, she provided her voice for multiple episodes of the TV series The Jetsons.
She is known for her childlike voice.
She married David Shire in 1982. The couple had a son named Daniel. She was also married to Frankie Conn from 1975 to 1978.
She starred in Grease with John Travolta.