Tuck made her television debut as Megan Gordon Harrison on the ABC daytime soap opera, One Life to Live. She was regular cast member from 1988 to 1992. She reprised the role in spirit form in 1993, 1999, 2004, and 2012. Tuck was nominated for a Daytime Emmy Award for Outstanding Lead Actress in a Drama Series in 1992 for her role on One Life to Live, but lost the award to her onscreen mother Erika Slezak. In 1990 she also was nominated for a Soap Opera Digest Award for Outstanding Female Newcomer: Daytime for the same role. After leaving daytime television, Tuck played Nicole Brown Simpson in The O.J. Simpson Story (1995) and had a leading role in the Olsen twins' straight-to-video movie Billboard Dad (1998).
From 1999 to 2005, Tuck co-starred opposite Amy Brenneman in the CBS drama series, Judging Amy as Gillian Gray. The series ended after six seasons. She later appeared in a number of films, most notable are Secretary (2002) and Super 8 (2011). She also appeared on High School Musical 2, High School Musical 3 and Sharpay's Fabulous Adventure as Darby Evans, the mother of Ryan (Lucas Grabeel) and Sharpay (Ashley Tisdale). In 2008, Tuck was cast in the HBO series True Blood as Nan Flanagan, a vampire who is the spokesperson and 'face' of vampires for the American Vampire League. In season 4, she was promoted to a series regular. She appeared in the series from 2008 to 2011 and made guest appearance in 2014, in the final season.
Tuck was born in New York City and attended Middlesex School. She graduated from Yale University with a BS in Psychology in 1986. She and her husband Robert Koseff have a daughter, Samara Barnes Hallam Koseff, born on March 24, 2003.
