More than 100,000 voted in the survey, which asked Digital Spy users to pick their favourite movies, music, gaming, tech and showbiz highlights from the past 12 months.
The King's Speech star emerged as the number one pick ahead of Harry Potter and the Deathly Hallows: Part 2's Daniel Radcliffe and Ryan Gosling, whose packed 2011 saw him appear in Blue Valentine, Drive and Crazy, Stupid, Love.
Harry Potter's Alan Rickman is at number four, followed by Rise of the Planet of the Apes's Andy Serkis in five. Serkis's performance capture turn as primate rebel Caesar has prompted calls for an Oscar nomination from studio 20th Century Fox and director Rupert Wyatt.
Firth won the 'Best Actor' Oscar in February this year for his portrayal of King George VI in The King's Speech. The monarch overcomes a crippling stammer with the help of Australian speech therapist Lionel Logue (Geoffrey Rush) to lead Britain to war.
Digital Spy readers' top 10 actors of 2011 are:
1. Colin Firth
2. Daniel Radcliffe
3. Ryan Gosling
4. Alan Rickman
5. Andy Serkis
6. Benedict Cumberbatch
7. Brad Pitt
8. Bradley Cooper
9. Gary Oldman
10. Jake Gyllenhaal
Watch Colin Firth in the trailer for The King's Speech below: