Claire Forlani was born on July 1, 1972 in London, England to a British mother and an Italian father who made his living managing a music producer. At age 11, Claire enrolled in London's Arts Educational School, where she studied dance and drama for the next six years. Her early theater credits include The Nutcracker Ballet at the Covent Garden and Orpheus in the Underworld at the Coliseum. In 1991, Claire ventured into the realm of UK television. She made two appearances on the series Press Gang (playing the part of Judy Wellman) and appeared on the program Shrinks. In 1992, Claire spent 11 weeks in war-torn Zagreb, Croatia, to appear in her first feature film Gypsy Eyes (released on video in the United States as C.I.A. Trackdown).

Claire and her parents relocated to San Francisco in 1993. Months later, she made her American debut in the ABC mini-series JFK: Reckless Youth, in the minor role of Ann Cannon, a tempting young lass who shares a sensuous dance with a young JFK. Claire next appeared in the 1994 sequel Police Academy 7: Mission to Moscow. Later that year, she played a small role in the 30-minute Showtime feature The Gift, which featured the likes of Isabella Rosellini and Mary Steenburgen and marked the directorial debut of Laura Dern. In 1995, Claire landed a role in Mallrats, the eagerly anticipated sophomore effort from Clerks writer-director Kevin Smith. Though Smith had auditioned over 600 hopefuls before he saw Claire, he was immediately taken with her spot-on impersonation of a callow American youth, and promptly offered her a role; only after they'd sealed the deal did he learn that Claire whose mannerisms and delivery had so impressed him was British. Mallrats gave Claire the exposure to help her land rolls in The Rock and Basquiat, in which she was touchingly effective as the sweet-natured waitress who wins the heart of artist Jean-Michel Basquiat. Also in 1996, she made her debut starring role in the independent short film Garage Sale, in which she played an earthy sort who strikes back at her faithless, fashion-model boyfriend by selling his wardrobe to pay her rent.