Margaret Welsh is an actress and writer, best known for Ratchet, A Killer Among Friends, Mr. & Mrs. Bridge and Smooth Talk. Other film credits include Are We There Yet?, The Wedding, Heading Home, Charlie's Ear, American Heart, Under the Cover of Darkness, Shadow of a Doubt and The New Kids. 

Television credits include Caitlin on ABC's Jake In Progress, Dorie Russell on ABC's Grey’s Anatomy, Anika on NBC's Providence and Holly Baker on NBC's American Dreamer. Guest appearances include Modern Family, Boston Legal, Without a Trace, The Practice, The Division, NYPD Blue, Diagnosis Murder, Judging Amy and Kate & Allie.

Theater credits include Marah, a.k.a. Mrs. Neuberger, in Young Playwrights Festival (Playwrights Horizons); Mary Garden/Suzanne Lenglen/Others in Big Bill (Lincoln Center/Williamstown Theatre); Leonide in The Triumph of Love (Classic Stage); Jean in Dead Man's Cell Phone (South Coast Repertory); and Helen in Under the Blue Sky (Geffen Playhouse).