Gagnier's notable roles include long running stints on daytime's One Life to Live, and Days of our Lives. She has been seen on television shows including Murder, She Wrote and Wings. She has guest starred on television's Dreamin On, Silk Stalkings, Baywatch (Gina Pomeroy) and ER. She has performed in theater productions both in New York and Los Angeles. On the big screen, she made her debut in New World Pictures, Girls Just Want to Have Fun. She has also made film appearances in Free Enterprise, The Return and Death Dance. Gagnier also played Mary-Angela, one of the many Tribbiani Sisters.