A graduate of New York University's prestigious Tisch School of the Arts, Clare earned her BFA in just three years.

While in New York, Clare appeared in numerous stage plays including one turn as Helen Keller in the stage version of "The Miracle Worker", the lead role in "Light Up the Sky" at the acclaimed Lee Strasberg Theater Institute, "Beyond Therapy" at the John Houseman Theater, and "Beginnings" at Circle in the Square. She began appearing in small and bit parts in films like In & Out (1997) and Vig (1998).

Clare first rose to attention as the hard-nosed cheerleader "Courtney" in the blockbuster hit Bring It On (2000) appearing alongside Kirsten Dunst and Eliza Dushku.

Immediately following, Clare was cast in a recurring role as "Glory", the vain hell-goddess on the television hit Buffy the Vampire Slayer (1997) which gained Clare additional acclaim as one of Buffy's most popular adversaries.

Clare has worked in both major studio and independent films, the most notable being Roger Avary's feature adaptation of Bret Easton Ellis' The Rules of Attraction (2002), as well as the villainous lesbian seductress "Lucy In the Sky" in the film D.E.B.S. (2003). She was also cast in lead roles in The Skulls III (2004), the independent film Mummy an' the Armadillo (2004), and an amusing small part in L.A. D.J. (2004) that she shot with good friend, Thomas Ian Nicholas.

She also appeared on television in a few guest appearances on Sabrina the Teenage Witch (1996), The Random Years (2002), and Tru Calling (2003). She continues to work for both stage and movie roles, most recently with the horror flick The Gravedancers (2006).

Clare is also active in various charities dating back to 1992 when she helped the Ohio's Recreation Unlimited and in 1993 when she served as a summer camp counselor at a YMCA camp for children with physical disabilities. During summer months from 1992 to 1997, she taught young adults with development disabilities at the Young Adult Institute in New York. She worked during the summer of 2000 at LA's Camp Laurel and participated in a 2002 bicycle race to raise money for Children International. Also in 2002, Clare rode her bicycle in the annual AIDS Ride, whereas participants ride over a seven day period that takes them from San Francisco to Los Angeles. In 2006, while on a trip to Australia and New Zealand with her husband, film producer Brian R. Keathley, Clare delivered school supplies to the small village of Tufi, Papua New Guinea.

Inspired by her trip to Papua New Guinea, Clare is in the process of launching her own charity (2012), named Giver (named after her two girls Gavin + River). Giver will focus specifically on kids living in impoverished nations. Clare is currently the official spokesperson for Kids 4 Kids, an organization that provides financial aid and toys for kids surviving with cancer.

Clare resides in Sherman Oaks with her husband and four children and has recently begun a career in directing.