The actor finally broke free of this typecast, and put himself in line for Oscar glory in 2010, with his powerful performance in Tom Ford-directed drama, A Single Man.
The pinnacle of his career, however, was marked by his role as stuttering King George VI in critcially-acclaimed film The King's Speech which won him a BAFTA, a Golden Globe, and finally, in February 2011, a coveted Oscar.
Colin Firth was born on September 10, 1960, and spent his early days in Nigeria, where his parents David and Shirley were both teachers. "Flamboyance on one side and classically English reserve on the other," is how he describes their influence.
The family moved back to England but relocated to America before Colin was a teenager. His childhood proved taxing as he never quite fitted in, even when the Firth brood once again crossed the Atlantic and settled in England.
A determined Colin, who'd announced his desire to be an actor at 14, enrolled at drama school, making do on a tight budget and living in a dilapidated London bedsit.
He made his West End debut in Another Country during his last year at the Drama Centre and was cast in the film adaptation soon after. TV and stage roles, including a high-profile part in The Secret Garden, followed, as did critical accolades and unending devotion from legions of female fans. But to their dismay, Colin fell for American actress Meg Tilly and was off the market.
The two met on the set of 1989's Valmont, the Milos Forman take on the famed Choderlos de Laclos novel Les Liaisons Dangereuses, and holed up in the Canadian backwoods for five years.
"I made furniture," recalls Colin of the time he spent in the forest while raising the couple's son William. Despite his own reclusive tendencies, however, the seclusion proved too much for Colin and the lovers eventually split amicably.
Colin later took up with his Pride co-star Jennifer Ehle, but while filming Nostromo in 1996, he fell in love with Livia Giuggioli, an Italian documentary maker who author Nick Hornby describes as "joke-perfect" - she's got both a PhD and sultry looks.
Colin and Livia wed on June 21, 1997, and welcomed their first son Luca in 2001 and their second, Mateo, in 2003.
"I feel much more settled and peaceful," reports Colin on marriage. Once again, however, he shies away from discussing that side of his life. "It was love at first sight or lust," he says of Livia. "She is an Italian beauty and the smartest woman on the planet. And this is as far as we're going in relation to my personal life! I'm no open book. There will never be a Colin Firth's Diary!"
His more recent work away from comedies has been a critical success, with his effort playing a grieving university lecturer in A Single Man who is coming to terms with the loss of his male partner being described as: "A quantum leap for Colin Firth… his most nuanced, compelling performance to date
And when 2011 brought the sort of movie success that most actors dream of, Colin accepted his Oscar in his typical, self-deprecating manner.
"I have a feeling my career just peaked," he joked, as he accepted the gong and dedicated it to his mother, Shirley. He thanked "all the people who have been rooting for me back home" and his wife Livia for "putting up with my fleeting delusions of royalty".
While he was delighted to be honoured with the award, the down-to-earth star was doubtless looking forward to getting back to reality.
"I think I'm feeling not joy – but relief that it's over. That seems to be the default position. You could say I'm grateful – and relieved," he said afterwards.