Vaudeville comedienne Billie Bird Sellen was discovered at an orphanage at the age of eight years and hired to tour theater circuits with a vaudeville troupe. During the Vietnam War she accompanied 12 USO tours entertaining the troops in the war zone in the 1960s and 1970s. She had worked as recently as 1995 when she appeared in Jury Duty (1995), starring Pauly Shore. Other notable performances were in Dennis the Menace (1993) and Home Alone (1990).

One of her best-known film appearances was in the 1968 movie The Odd Couple (1968). Her last appearance was a cameo in 1997 in the short-lived television comedy George & Leo (1997) with Judd Hirsch and Bob Newhart. She had also been a regular from 1988-1992 in the sitcom Dear John (1988), and in a series of performances as a cheerful and sassy senior citizen in such productions as Ernest Saves Christmas (1988) and Police Academy 4: Citizens on Patrol (1987).