The actor, 30, tops the list for 2018, compiled by GQ magazine.
The top 10 also features politician Jacob Rees-Mogg in fourth place, documentary maker Louis Theroux (seventh), music producer and DJ Marshmello (eighth) and The Body Coach Joe Wicks (10th).
But there is better news for The Crown star and former Doctor Who Matt Smith, 35, who is named best-dressed man.
He is followed by US rapper A AP Rocky, The Fly star Jeff Goldblum and singer Harry Styles.
Brooklyn Beckham, the son of former pop star Victoria Beckham and ex-footballer David, scooped ninth place.
Actors Andrew Garfield, Riz Ahmed and Ryan Reynolds, and grime artist Skepta also make the top 10.
The list is voted for by GQ staff alongside experts from the fashion and celebrity worlds, including Giorgio Armani, Christopher Bailey, Tommy Hilfiger, Michael Kors and Sir Paul Smith.
The worst-dressed top 10 also includes comic Paul Merton, YouTube supercar expert Shmee150, singer Morrissey, business magnate Elon Musk and PewDiePie, the vlogger Google distanced itself from earlier this year over allegations of anti-Semitism.
The Best and Worst-Dressed Men Lists are in the January 2018 issue of GQ, available on newsstands from Monday December 4.
GQ Best-Dressed Men 2018
1. Matt Smith
2. A AP Rocky
3. Jeff Goldblum
4. Harry Styles
5. Andrew Garfield
7. Riz Ahmed
8. Ryan Reynolds
9. Brooklyn Beckham
10. Alessandro Michele
1. Kit Harington
2. Paul Merton
4. Jacob Rees-Mogg
7. Louis Theroux
9. Elon Musk
10. Joe Wicks