For his roles on television, he received Primetime Emmy Award nominations for his portrayals of Dr. Wilhelm Stuckart in the BBC film Conspiracy (2001), and Michael Peterson in the HBO limited series The Staircase (2022).

"[17] However, at Barton Peveril Sixth Form College in Eastleigh, he was imbued with a love of English literature by an enthusiastic teacher, Penny Edwards, and has said that his two years there were among the happiest of his life.

Lawrence was severely injured at the Battle of Mount Tumbledown during the Falklands War, and the film details his struggles to adjust to his disability whilst confronted with indifference from the government and public.

[30] Firth finally became a British household name through his role as the aloof, haughty aristocrat Mr. Darcy in the 1995 BBC television adaptation of Jane Austen's Pride and Prejudice.

[32] Sheila Johnston wrote that Firth's approach to the part "lent Darcy complex shades of coldness, even caddishness, in the early episodes".

[27] The series was an international success and unexpectedly elevated Firth to stardom[32]—in some part due to a scene not from the novel, where he emerges from a lake swim in a wet shirt.

[33] Although he did not mind being recognised as "a romantic idol as a Darcy with smouldering sex appeal"[34] in a role that "officially turned him into a heart-throb",[35] he expressed the wish not to be associated with Pride and Prejudice forever.

[37] The most notable was his casting as the love interest Mark Darcy in the film adaptation of Bridget Jones's Diary, itself a modern-day retelling of Pride and Prejudice.

Prior to this, Firth had a significant supporting role in The English Patient (1996) as the husband of Kristin Scott Thomas's character, whose jealousy of her adultery leads to tragedy.

He appeared in several television productions, including Donovan Quick (an updated version of Don Quixote) (1999),[42] and had a more serious role as Dr. Wilhelm Stuckart in Conspiracy (2001), concerning the Nazi Wannsee Conference, for which he was nominated for a Primetime Emmy Award.

[50] He played painter Johannes Vermeer opposite Scarlett Johansson in the 2003 release Girl with a Pearl Earring; some critics praised the film's subtlety[51] and sumptuous visuals,[52] whilst others found it almost restrained, tedious and bereft of emotion.

In 2005 Firth appeared in Nanny McPhee with Emma Thompson, in which he plays a struggling widowed father, it was a rare venture for him into the fantasy genre.

[55] He also appeared in Where the Truth Lies, a return to some of his darker, more intense early roles, that included a notorious scene featuring a bisexual orgy.

[56] Sheila Johnston wrote that it "confounded his fans", but nonetheless that his character "draws knowingly on that suave, cultivated persona",[57] which could be traced from Mr. Darcy.

[60] Manohla Dargis in The New York Times said: "It's a pleasure to watch Mr. Firth–a supremely controlled actor who makes each developing fissure visible–show the adult Blake coming to terms with his contradictory feelings, letting the love and the hurt pour out of him.

[67] Like Love Actually, it polarised critics, with supporters such as Empire calling it "cute, clean, camp fun, full of sunshine, and toe tappers",[68] whereas Peter Bradshaw in The Guardian said the film gave him a "need to vomit".

[72] In 2009 he appeared in A Christmas Carol, an adaptation of Charles Dickens' novel, using the performance capture procedure, playing Scrooge's optimistic nephew Fred.

[73] At the 66th Venice International Film Festival in 2009, Firth received the Volpi Cup for Best Actor for his role in Tom Ford's directorial debut A Single Man, as a college professor grappling with solitude after the death of his longtime partner.

[85][86] Empire's Kim Newman wrote, "Firth starts out homaging Caine with his horn-rimmed cool but soon defaults to his usual repressed British cold mode",[87] whilst Time Out London called his a "likeable performance", although criticised the film overall.

[88] Stephen Dalton in The Hollywood Reporter said, "To his credit, Firth keeps his performance grounded in downbeat realism while all around are wildly mugging in desperate pursuit of thin, forced laughs.

[92] In May 2013, it was announced that Firth had signed to co-star with Emma Stone in Woody Allen's romantic comedy Magic in the Moonlight, set in the 1920s and shot on the French Riviera.

[95] In June 2015, he began filming the story of amateur yachtsman Donald Crowhurst in The Mercy, alongside Rachel Weisz, David Thewlis and Jonathan Bailey.

[99] In 2017, he reprised his role as Jamie from 2003's Love Actually in the television short film Red Nose Day Actually, by original writer and director Richard Curtis.

[102] That year, he also appeared as William Weatherall Wilkins in the musical fantasy film Mary Poppins Returns, starring Emily Blunt in the title role.

It features contributions from many Western writers, including Laurens van der Post, Noam Chomsky, Claude Lévi-Strauss; and from Indigenous people such as Davi Kopenawa Yanomami and Roy Sesana.

[118] In December 2010, Firth was guest editor on BBC Radio 4's Today programme, where he commissioned research to scan the brains of volunteers (mostly university students) to see if there were structural differences that might account for political leanings.

[7] The resulting academic paper listed him as an author, along with two University College London researchers[119][120] and the science reporter of the BBC Radio 4 Today programme.

[125] As a supporter of the Refugee Council, Firth was involved in a campaign to stop the deportation of a group of 42 Congolese asylum seekers, expressing concerns in open letters to The Independent and The Guardian that they faced being murdered on their return to the Democratic Republic of Congo.

During the filming of Pride and Prejudice, Firth and co-star Jennifer Ehle began a romantic relationship, which received media attention only after their separation.

Following the referendum's passage, and the ensuing uncertainty over rights of non-EU citizens, he applied for "dual citizenship (British and Italian)" in 2017 to "have the same passports as his wife and children".