The youngest child of a Jewish mother whose family fled Germany in the late 1930s and a Scottish foundling jailed for his pacifist beliefs, Cartlidge began her career in the theater, first working as a dresser for actress Jill Bennett and then as a performer in fringe theater before moving to more "legit" work such as playing Juliet. She made headlines in the London tabloids when she was atypically cast as a violent schoolgirl in the premiere of the popular serial "Brookside" in 1982. After a year on the drama series, Cartlidge returned to the stage to hone her craft, making the occasional appearance on TV (e.g., "Sacred Hearts" 1984) or in film (a cameo in "Eat the Rich" 1987).
Director Mike Leigh was impressed with the actress and cast her in the breakthrough role as the bitter punk bedmate of a grungy loser (David Thewlis) in "Naked". Other roles quickly followed, including Carine Adler's short "Fever" (1994, the precursor of the director's 1997 feature "Under the Skin"), in which she played a promiscuous woman, and the Oscar-nominated foreign film "Before the Sun" (1994), as the married lover of a Macedonian-born photographer. Lars von Trier then cast her as Emily Watson's overprotective sister-in-law in "Breaking the Waves" (1996). While Watson had the showier part and thereby garnered all the acclaim, Cartlidge matched her intensity and to paraphrase Janet Maslin's The New York Times review, represented the rationality which the movie ultimately abandons.
Reteaming with Mike Leigh, Cartlidge starred as the acerbic Hannah, one of the titular "Career Girls" (1997), university chums whose reunion makes them realize where they've been and where they are. The actress then adopted an American accent to star as "Claire Dolan" (1998; released in the USA in 2000), a working girl who attempts to leave behind that way of life in order to have a child. Cartlidge, who was in virtually every scene of the film, bravely undertook this complex and contradictory role and delivered an astonishing tour de force that was nothing short of brilliant. Abandoning contemporary times, the actress played Varya in Michael Cacoyannis' long-awaited filming of Chekhov's "The Cherry Orchard" and then made a cameo appearance as the owner of a Parisian brothel frequented by Sir Arthur Sullivan in Leigh's "Topsy-Turvy" (both 1999).