Mary Gallagher is an actor, stand-up comedian and writer. She is best known for appearances on Friends, The West Wing and The Late Show with Stephen Colbert, as well as films, including Flightplan and How Do You Know.

Originally from Elm Grove, Wisconsin, Mary graduated from The University of Wisconsin - Green Bay, receiving the Chancellor's Medallion for her acting, writing and directing. She and Amy (Ketchum) Holterman formed "The Flying Napkins" presenting comedy to promote social awareness in health and sex education. In 2021, Mary was presented with UWGB's Distinguished Alumni Award.

As a stage actor, her performances of Who's Afraid of Virginia Woolf, King Lear, Tartuffe, and In Circles gained her a nomination for the American College Theatre Festival's Irene Ryan Award, and she also took first place in the 15 Minutes of FEM competition at the Egyptian Theater in Hollywood, playing her character Shelby Gratt.

After graduating from UWGB, Mary trained at Second City of Chicago and toured nationally with the improvisation group Wavelength. She was a lead in Rob Reiner's NBC pilot Everyday Life and Jason Alexander's Let Bob Do It for Nickelodeon, and she was the host of the pilot The Short Show for E! Networks, the co-host of Game Show Network's cult classic Faux Pause, and co-host of NBC/PAX-TV's World Cup Comedy (with Dan O'Connor), produced by Kelsey Grammer.

In 2018 Mary had her national television stand-up comedy debut on The Late Show with Stephen Colbert. Other filmed stand-up comedy performances include Amazon's Laugh After Dark and a 2022 Dry Bar Comedy special. In 2019, her series Be My Therapist (co-created with Brian Kiley) was a finalist at The Montreal Just For Laughs Festival, and she's been a semi-finalist in Comedy Central's Laugh Riots competition and in the Andy Kaufman Award competition for The New York Comedy Festival as a stand-up comedian.