Cavanagh was an original member of the professional theatre troupe New Age Vaudeville founded by Richard O'Donnell and Amy McKenzie. An Actor's Equity theatre troupe, the Comedy Cabaret landed a summer residence at Peninsula Players in Fish Creek, Wisconsin, where it developed works for a predominately tourist trade and then relocated to their winter home in Chicago at CrossCurrents. Throughout her tenure, Megan Cavanagh starred in numerous productions including the cult-hits An Evening with Elmore & Gwendolyn Putts - The Neighbors Next Door and The TV Dinner Hour. Rick Kogan of the Chicago Tribune hailed both productions as "Among the most polished and clever productions of the season, a pair of devilishly inventive and challenging shows that won over critics and audiences".
Film
Cavanagh made her film debut in Penny Marshall's A League of Their Own starring Tom Hanks, Geena Davis, and Lori Petty. Film critic Vincent Canby of the New York Times praised the film writing ""A League of Their Own" is one of the year's most cheerful, most relaxed, most easily enjoyable comedies. It's a serious film that's lighter than air, a very funny movie that manages to score a few points for feminism in passing." He went on to list Cavanagh as among "the excellent supporting players", as did film critic Jonathan Rosenbaum of the Chicago Reader. Following her film debut, Cavanagh was cast in two Mel Brooks' comedies. The supporting roles were Broomhilde in ' and Essie in '. Other films include supporting roles in Ivan Reitman's Junior starring Arnold Schwarzenegger, Danny DeVito, and Emma Thompson, and Disney's That Darn Cat starring Christina Ricci and Doug E. Doug. She voiced Judy Neutron and Sasha Vortex in the Oscar-nominated animated feature .
TV
Cavanagh was featured in the short-lived second season of Bob and played the recurring role of Trudy McHale, who married Al Borland in the series finale, on the sitcom Home Improvement starring Tim Allen, Patricia Richardson and Earl Hindman. Openlylesbian, Cavanagh starred in Exes and Ohs, a lesbian comedy on Logo TV. She reprised the role of Judy Neutron in and several TV movies including The Jimmy Timmy Power Hour, Jimmy Neutron: Win, Lose and Kaboom, and The Jimmy Timmy Power Hour 2: When Nerds Collide. She also voiced Slog in Tak and the Power of Juju and Hilary Higgenbottom in The Mighty B!. She appears in the American sitcom Friends as Luisa the ex-classmate of Rachel and Monica who works for animal control. She is only in one episode. Cavanagh makes an appearance in Season 3, Episode 4 of Will and Grace entitled "Girl Trouble." She plays Terry.
Stage
Cavanagh returned to the stage completing a 10-city tour as Earth Mother in. Theater critic Patricia Reardon wrote, "...you won't find a funnier, more satisfying way to spend an evening than with the four rollicking ladies of Menopause The Musical." In 2009, Cavanagh performed the medium Madame Arcati in High Spirits, a musical with a book, lyrics, and music by Hugh Martin and Timothy Gray, based on the play Blithe Spirit by Noël Coward. 42nd Street Moon's production was staged at the Eureka Theatre, 215 Jackson St in San Francisco, and was well received. San Francisco theater critic Chad Jones writes, "On Broadway, Lansbury is said to be divine in the role, but 42nd Street Moon has a real secret weapon here: Megan Cavanagh,...Cavanagh is hilarious and heartfelt."
Personal life
Cavanagh married her wife, filmmaker Anne Chamberlain, in 2008. They divorced in 2020, with Chamberlain citing "irreconcilable differences".
