The youngest of two, Michigan native Watros was raised in near poverty after her parents were divorced. While her mom struggled to feed and clothe two kids by holding down two jobs, the future star faced a life-threatening illness when she hit high school. Diagnosed with immune thrombocytopenia purpura (ITP), a disease that causes bleeding through the skin, she spent nearly three years in and out of hospitals undergoing chemotherapy and eventually a splenectomy. Graduating from high school, Watros marked time at a local community college until she was cast as Agnes Gooch in a production of "Auntie Mame". Transferring to Boston University, Watros graduated with a BFA and like many, headed to NYC to seek fame.
After marking time as a waitress, she landed a small role on Fox's "New York Undercover" and then was cast in her star-making role as the virginal nurse Annie Dutton on CBS' long-running "Guiding Light" in 1994. Over her three years on the daytime drama, her character went from sweet good girl to psychotic, allowing the actress to display her range. Although she clashed with resident diva (and on screen rival) Kim Zimmer, Watros proved popular with fans and took home the 1998 Daytime Emmy as Best Lead Actress. By that point, though, she had decided to try her hand at other roles and had decided not to renew her contract with the show.
While she had a couple of film roles ("Cafe Society" 1996) under her belt, Watros headed West for pilot season. Although she made "Rock Paper Scissors" for Fox, it didn't make it to the fall schedule. She briefly returned to daytime filling in for an ill actress in the role of Vicky Hudson McKinnon on "Another World" in late 1998. The following year, she auditioned and was offered the role of Erin in the pilot of "Titus", but Fox ironically wanted to pay her less money than she had received for "Rock Paper Scissors". As a result, she spurned the offer but after an exhaustive search, the "Titus" producers pressured the network to meet her financial demands. As a result, Watros enjoyed critical acclaim for her work and further got to demonstrate her comedic abilities. Like others who have enjoyed success on the small screen, the actress was courted for other parts and accepted a supporting role in Faye Dunaway's directorial debut, the short "The Yellow Bird" (2001) and a co-starring part in Steve Guttenburg's directorial debut, "P.S. Your Cat Is Dead" (2003).
After the cancellation of "Titus," the producers of ABC's long-running sitcom "The Drew Carey Show" quickly snatched up Watros in the 2002 season to fill the distaff void left by departing actress Christa Miller, casting her as Kellie Newmark, Drew's childhood friend who has long carried a torch for him. Watros stayed with the show through its final season in 2004. She was not absent for the small screen for long, cast on the hit ABC series "Lost" as Libby, a therapist who was part of a second band of survivors of the airplane crash discovered in the second season.