John Ingle, formerly the chairman of the Beverly Hills High School art department, later commented that Kavner was "excellent at improvisation, but she wasn't an ingenue and not that castable at that age". After graduating from high school, Kavner attended San Diego State University and majored in drama, being cast in several productions including a role as Charlotte Corday in "Marat/Sade", becoming known for her improvisation and ability to do both comedy and drama. After graduating in 1971, she got a day job as a typist at the UCLA School of the Arts and Architecture. In 1973, Kavner auditioned for a role as one of Rhoda Morgenstern's sisters in "The Mary Tyler Moore Show". David Davis, producer of the show, had convinced her to audition for the part, but decided to cast another actress instead. A year later, Rhoda Morgenstern became the leading character in a spin-off called "Rhoda". Kavner was cast in her first professional acting role as Brenda Morgenstern, sister of the eponymous character. "Rhoda" ran on CBS from September 9, 1974, to December 1978. She received four Primetime Emmy Award nominations for Outstanding Continuing Performance by a Supporting Actress in a Comedy Series for playing Brenda, winning in 1978. She also received four Golden Globe Award nominations. In 1975, she received Daytime Emmy Award nomination for her starring role in the daytime special "The Girl Who Couldn't Lose". Following "Rhoda", Kavner had a guest appearance on "Taxi" and appeared in the 1985 comedy "Bad Medicine" as well as the 1987 film "Surrender", both of which were box office failures. She appeared in the television movies "Revenge of the Stepford Wives", "No Other Love" and "A Fine Romance", and shot a television pilot. She also starred in several stage plays, including a play called "It Had to Be You" at a dinner theater in Canada, "Particular Friendships" in New York City in 1981, and "Two for the Seesaw", directed by Burt Reynolds. Woody Allen first saw Kavner one night while he was watching "Rhoda" in the 1970s. He thought that she was remarkable and later offered her a role in his 1986 film "Hannah and Her Sisters". Kavner agreed, and credits Allen and the film with rejuvenating her career. Kavner was then cast as a sidekick to Tracey Ullman in "The Tracey Ullman Show", which debuted on Fox in 1987.