Richardson debuted professionally at the Manchester Library Theater in 1979 and two years later made it to London's West End in "Moving.” Shortly thereafter, she appeared for the first time as a pregnant au pair seeking guidance from a newspaper columnist in the British sitcom "Agony.” 1984 proved to be a banner year with a role in the syndicated TV miniseries "A Woman of Substance," her initial collaboration with director Mike Newell on the stage play "Life of Einstein" and her feature acting debut in "The Innocent.” The following year, Newell cast her in the central role of Ruth Ellis, the tart murderess who was the last woman hanged in England, in the period drama "Dance With a Stranger.” With brassy platinum hair and a hard-shell demeanor, Richardson shined in the role and rose above the clichéd material.

The actress went on to hone her comedic skills playing Queen Elizabeth I and becoming a member of the stock company of Rowan Atkinson's "Blackadder" series. Having seen her in "Dance With a Stranger,” director Steven Spielberg tapped her to play a female prisoner in a Japanese internment camp who becomes a surrogate mother to a young boy (Christian Bale) in the underrated "Empire of the Sun" (1987). For much of the 1980s, Richardson—who has stated a preference for working on stage—alternated between the theater and television, acting in the London premiere of Sam Shepard's "A Lie of the Mind" (1987) and Harold Pinter's "Mountain Language" (1988) and reuniting with Atkinson and company for "Blackadder's Christmas Carol" (BBC, 1988) and "Blackadder Goes Forth" (BBC, 1989).

As the 1990s rolled around, Richardson made the first of several appearances on the British variety series "The Comic Strip" and didn't worry that other’s interest in her as a film actress had diminished. Once again Mike Newell provided a break, hiring her to play a society matron who shares an Italian villa with three other British women in "Enchanted April" (1991; released in the USA in 1992). Neil Jordan then cast her as the sexy but tough as nails IRA member in "The Crying Game" (1992) and Louis Malle tapped her to play the wife of a politician who begins an affair with their son's girlfriend. It was during the latter film that reports of her difficulty began making their way into print. While Malle and co-star Jeremy Irons couched their praise for her talent, they also hinted of problems with the actress. Whatever the case, she had scored back-to-back triumphs, earning critical huzzahs and accolades, including an Academy Award nomination for Best Supporting Actress Sfor "Damage.”

In 1994, the actress offered a mesmerizing turn as the mentally trouble first wife of poet T.S. Eliot in "Tom and Viv,” and her efforts were rewarded with a Best Actress Academy Award nomination. Still determined to work on her own terms, she eschewed most of the offers to act in sub-par American films, instead appearing in the HBO film "Fatherland" (1994) and making a riotous guest appearance as a harried new mother on the cult hit "Absolutely Fabulous.” Robert Altman cast her to great effect as the drug addicted wife of a politician kidnapped by a desperate wife in his otherwise dull ode to jazz in "Kansas City" (1996). Later that year, Richardson effectively stole the proceedings as the best friend of the now deceased Emma in "The Evening Star", the disappointing sequel to "Terms of Endearment.”

She returned to the London stage opposite Mike Nichols (in a rare acting role) in Wallace Shawn's play "The Designated Mourner" under the direction of David Hare (the production was filmed and received a limited theatrical release in 1997) before adopting another flawless American accent in "The Apostle" (1997), Robert Duvall's labor of love that cast her as one of his love interests. Back-to-back high profile role in NBC miniseries followed: the evil Queen Mab in "Merlin" (1998) and the Queen of Hearts in "Alice in Wonderland" (1999). Despite the lavish productions, Richardson managed to make an impression. She followed up as the unhappy, wealthy wife of a political candidate in "The Big Brass Ring" (Showtime, 1999), based on a script by the late Orson Welles.

Richardson returned to the big screen as the mysterious stepmother of Christina Ricci in Tim Burton's lavish reworking of the American legend of "Sleepy Hollow" (1999). Richardson joined Rowan Atkinson and others for the short film "Blackadder Back and Forth" which debuted at Greenwich's Millennial Dome in the waning days of 1999. She then lent her distinctive vocal talents to the highly anticipated animated feature "Chicken Run" (2000) and joined Sylvester Stallone and Rachael Leigh Cook (as her daughter) in the remake of "Get Carter" (also 2000). She made a delightfully wicked Queen Elspeth in the USA Network telepic "Snow White: The Fairest of Them All" (2001) before returning to movie theaters in a pair of films centered on emotionally harrowing subject matter: "Spider" (2002), in which she played the mother of a schizophrenic; and "The Hours" (2002), playing Virginia Woolf's sister Vanessa Bell, who has a complicated relationship with her sibling to say the least. After playing the Queen of Denmark in the made-for-Julia Stiles romantic comedy, “The Prince & Me” (2004), Richardson appeared in “Andrew Lloyd Webber’s Phantom of the Opera” (2004), directed by an over-exuberant Joel Schumacher. With a faux-French accent more outlandish than Inspector Clouseau’s, Richardson played Madame Giry, the stern grande dame of an opera house where the mysterious phantom likes to spend his spare time. Despite lavish production values, a built-in audience and high expectations, the musical failed to wow critics or attract large crowds to the box office.