Jessalyn Gilsig began her acting career at age 12. She later graduated from McGill University in 1993 with a degree in English. She also studied at the American Repertory Theater.
Gilsig started as a voice actress, contributing to the films Mascarade and The Journey Home, as well as several animated series. She then moved to New York to perform in several off-Broadway productions. Her first big break came in 2000, when David E. Kelley - who previously had her guest in his shows The Practice and Snoops - cast her in Boston Public, where she'd stay for two seasons.
Gilsig then joined the cast of Nip/Tuck as sex addict Gina Russo, a role she held until 2008. The show's creator, Ryan Murphy, later cast her in another one of his shows, Glee: there she played Terri Schuester, the obsessed wife of Matthew Morrison's Will Schuester.
Gilsig also had recurring roles in Prison Break, Friday Night Lights and Heroes, and also appeared in films such as The Horse Whisperer and Flood. She was previously married to film producer Bobby Salomon, until she filed for divorce in 2010; they have a daughter, Penelope.
Gilsig can now be seen in the new History Channel television series Vikings