After a career playing the smouldering romantic interest in a series of successes including Bridget Jones's Diary and The English Patient the actor is taking on more challenging roles.
This impressive move to avoid typecasting in films like The Importance of Being Earnest and What A Girl Wants paid off when he landed a best actor BAFTA for A Single Man.
Firth joined the National Youth Theatre aged 18 and spent two years at London's Drama Centre before attracting attention for Hamlet in his final term.
Although as a child Colin had expressed interest in acting, he was 18 when he began to pursue his studies in earnest, joining the National Youth Theatre.
He made his film debut in the 1984 version of the public school drama Another Country alongside Rupert Everett.
In 1986, he solidified his standing as a rising star with the miniseries Lost Empires, and the following year gave a strong portrayal of a haunted WWI veteran in A Month in the Country.
Following that he appeared in the lavish and very successful Dangerous Liaisons playing the title role of the duplicitous count Valmont.
The part also marked the beginning of his relationship with Meg Tilly.
The following year he attracted controversy in the Falklands drama Tumbledown, in which he played war hero Timothy Lawrence.
Firth gained worldwide admirers and a BAFTA nomination for his turn as the dashingly handsome Mr. Darcy in the 1995 TV adaptation of Jane Austen's Pride and Prejudice.
He portrayed a foul-mouthed football player in 1997's Fever Pitch, and a year later cut a dashing figure as the Earl of Wessex, the intended groom of Gwyneth Paltrow's Viola, in the Oscar-winning Shakespeare in Love.
That year he also married Italian born Livia Giuggioli whom he met a year earlier during the filming of Nostromo. In 2001, their son Luca was born in Rome.
The same year he played Mr Darcy again, a character inspired by Jane Austen's Darcy, but this time it was opposite Renee Zellweger's title character in the feature version of Bridget Jones's Diary.
Confounding stereotype, he next played villainous Nazi Dr Wilhelm Stuckhart in the excellent BBC drama Conspiracy about the Wannsee conference which decided the Final Solution.
Shifting gears, he next tackled Shakespeare's Melancholy Dane in a stage production of Hamlet, before returning to the screen in a remake of The Importance of Being Earnest and the faltering Hope Springs.
Subsequent roles included an aristoctat (again) in the lukewarm What A Girl Wants and he also appeared in the romance-by-numbers Love Actually with Liam Neeson and Rowan Atkinson.
Against type, he also played the delusional widower Ben in Marc Evans' disappointing psychological thriller Trauma before returning tothe role of Mr Darcy in Bridget Jones: The Edge of Reason.
Next up was the mystery thriller Where The Truth Lies and he switched to comedy to provide an enjoyable turn as the put-upon widower in Nanny McPhee opposite Emma Thompson.
He impressed in the biographical drama When Did You Last See Your Father only to return to Helen Hunt's rom-com staple Then She Found Me in 2007.
Lightweight roles continued with St Trinian's and Mamma Mia! before he sold his soul as the dissolute Lord Henry Wotton in Dorian Gray.
In 2009, American fashion designer turned director Tom Ford cast him as the grieving gay British lecturer George in the heartfelt A Single Man.