[4][non-primary source needed] Beamish began acting early, starring in TV movies as a child during the 1980s, before finding series work on television in the 2000s, making appearances on CSI, Gilmore Girls, and Six Feet Under.
[6] Her role in Shortbus was praised by David Ansen in Newsweek, who said "Beamish's conflicted dominatrix stands out for her understatement, she understands nuance and stillness.
[10] In 2013, Beamish starred in Nate Taylor's Forgetting the Girl, her performance praised by David DeWitt in The New York Times.
[11] While attending grad school at UC Davis, Beamish devised, directed and starred in the multi-media performance 38 1/2, and Wigs,[12] created with and co-starring Amanda Vitiello.
[13] In 2019, Beamish and Vanessa Peters wrote, directed and starred in the award-winning[14] The Institute for the Opposite of Longing, which ran for multiple dates in Boston[15] and Los Angeles.