At the start, Otis Harris, Jeremy Wariner, and Derrick Brew stormed out from the blocks to take a powerful lead over the rest of the field.

Slightly behind coming off the turn, Wariner stormed ahead over the last hundred metres to win the race at 44.00 seconds, the fastest time ever recorded in this event since American legend Michael Johnson won the gold in Sydney 2000.

[3] At the end of the final, seven sprinters managed to finish the race under 45 seconds, and five personal bests were recorded.

None of the finalists from 2000 returned; the only medalist from the 2003 world championships to compete was bronze winner Michael Blackwood of Jamaica.

The American team of Jeremy Wariner, Otis Harris, and Derrick Brew was strong, even without two-time defending champion Michael Johnson, who had retired.

For the men's 400 metres, each National Olympic Committee was permitted to enter up to three athletes that had run the race in 45.55 seconds or faster during the qualification period.