Other 2011 Best-Dressed List also features Doctor Who's Matt Smith in 12th, his first time in the poll, with Little Britain star David Walliams at 11, David Beckham at 16 and Prime Minister David Cameron, who has dropped from eighth place last year, at 20.
Best-Dressed winner Johnson, who last year fathered a baby girl with 43-year-old fiancee Sam Taylor-Wood, scooped first place from last year's winner, Twilight heart-throb Robert Pattinson.
Elsewhere in the coveted annual list, X Factor host Dermot O'Leary, a new entry at 40, beats his boss Simon Cowell, who ranks at 43.
The top 50 also includes racing driver Jenson Button (9), British rapper Tinie Tempah (15), Sir Elton John (21), Ray Winstone (28), Jude Law (29), music producer Mark Ronson (34), Sherlock star Benedict Cumberbatch at 41 and artist David Hockney at 47.
GQ said: 'Our list goes right down to a frighteningly tuned-in (and well-connected) eight-year-old, taking in anyone from actors, aristocrats and hip-hop artists to fashion designers and Formula One drivers along the way.'
Mel Gibson tops the list of Worst-Dressed Men In The World, which also features Jonathan Ross and shadow education secretary Andy Burnham
The TOP 30
1. Aaron Johnson
2. Douglas Booth
3. Nicholas Hoult
4. Robert Pattinson
5. Prince Harry
6. David Furnish
7. Tom Ford
8. Alex James
9. Jenson Button
10. Bill Nighy
11. David Walliams
12. Matt Smith
13. Dominic Cooper
14. Patrick Grant
15. Tinie Tempah
16. David Beckham
17. David Gandy
18. Adrien Sauvage
19. George Lamb
20. David Cameron
21. Sir Elton John
22. Ben Barnes
23. Theo Hutchcraft of Hurts
24. Tom Hardy
25. William Gilchrist
26. Romeo Beckham
27. Prince William
28. Ray Winstone
29. Jude Law
30. Jarvis Cocker
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