John Billingsley was born in Media, Pennsylvania, to a family that moved frequently in his early years. When they settled in Weston, Connecticut, Billingsley appeared in school plays and went on to study theatre at Bennington College in Vermont. Later, he moved to Seattle where his acting talents were showcased in numerous regional stage productions. In 1989 Billingsley founded Book-It Repertory Theatre, a Seattle-based theatre company devoted to adapting fiction to the stage, where he spent five years directing and performing shows. He also co-founded Freehold, a Seattle acting studio.

Billingsley currently stars as the Denobulan Dr. Phlox on Enterprise. In addition, he stars opposite Denzel Washington in the feature film "Out of Time" and has appeared in "Crocodile Dundee in Los Angeles," "The Glass House," "High Crimes" and "White Oleander." He also starred in the independent film "Breathing Hard," which won a number of awards on the festival circuit. He was a series regular on The Others and guest starred in other television series including The West Wing, Family Law, Judging Amy, NYPD Blue, Gideon's Crossing, The Practice, The X Files and Six Feet Under.

Billingsley's Los Angeles stage credits include productions at the theatre company A Noise Within in such plays as "The Winter's Tale," "Twelfth Night," "Great Expectations" and "The Country Wife." With the Los Angeles company The Actors' Gang, he performed in "Ugly's First World," and he toured in Europe with Milwaukee's Theatre X in "A History of Sexuality." He also trod the boards of the prestigious Seattle Repertory Theatre in "Nothing Sacred."

Billingsley currently resides in Los Angeles with his wife, actress Bonita Friedericy, and their two cats.