Mary grew up in the small beach community of Long Beach Island, New Jersey. Mary graduated from NYU's Tisch School of the Arts where she earned her BFA in acting, and was also awarded the Stella Adler Award for Outstanding Achievement in Acting.

Mary made her Broadway debut in "Martin Short: Fame Becomes Me" in 2006, for which she won the prestigious Theatre World Award. Mary also stared as rookie cop "Deputy Kimball" in Reno 911 on Comedy Central, and in the Fox feature film "Reno 911: Miami."

She has performed in several shows on Comedy Central-- appearing regularly on the network in "Crossballs," Contest Searchlight w/Dennis Leary and "The Daily Show w/Jon Stewart." Mary has appeared in numerous TV pilots, including CBS' "Rubbing Charlie" (starring Scott Wolfe), a FOX sitcom starring James Caan and Jill Clayburgh, the role of "Connie" in CBS' "Welcome to New York" with Christine Baranski, and a co-starring role with Cheri Oteri in the sitcom pilot, "Loomis." Mary has appeared as a guest star on "Normal People" (FOX TV pilot with Tori Spelling), and "Talk To Me" (ABC sitcom w/Kyra Sedgwick). She has done guest spots on MTV's "Apt. 2F," NBC's "ED" & "Late Night With Conan O'Brien" & "The Howard Stern Show" on E!. As a writer/performer Mary created 25+ original characters in the NBC sketch comedy pilot, "Live On Tape". But Mary is no stranger to the legitimate stage.

She trod the boards in the very UN-legitimate role of "Vixen Fox" (a porn star) in Elaine May's off-Broadway comedy "Adult Entertainment" with Danny Aiello and Jeannie Berlin at the Variety Arts Theatre in NYC. Other theatre roles include "Portia" in the Moonwork production of "Julius Caesar" in New York City, and "Victoria Fitch" in the musical "Palm Beach." She wrote and starred in the one-woman off-Broadway show "Judy Speaks" at the Ars Nova Theatre in New York City, and at Playhouse Merced in CA. She also wrote/starred in a series of one-acts for her alter-ego, the 1940s B-movie star Janet Lamé, who made her small screen debut on NBC's variety show "Late Friday." She has also performed her other one-woman shows "The Very Mary Birdsong Show" & "The Respectable Race" in L.A. at the HBO/WB Workspace and in New York @ PSNBC. Other film credits include "Beer League" (w/Artie Lange), "Pizza," "Le Chase," "Above Freezing," "Let It Snow," "In God's Hands," (starring Peter Sarsgaard) and "The Last Request" (starring Danny Aiello.)