Athletics at the 1976 Summer Olympics – Men's 400 metres

In the final, Fred Newhouse and Maxie Parks appeared to go for the early lead, while Alberto Juantorena was initially a little slower. Then he stretched out on the backstretch to regain position about equal to the third American Herman Frazier. Coming off the final turn Juantorena had caught the rest of the field and was a step behind Newhouse. Parks and Fons Brijdenbach were about even two more strides back with Frazier just behind them. As Juantorena began to pass Newhouse, Newhouse noticeably struggled, rocking and losing form, then the gold medal. Three metres back, Frazier just edged ahead of Brijdenbach for the bronze medal, as Parks faded.[7][8][9][10]

This was the eighteenth appearance of the event, which is one of 12 athletics events to have been held at every Summer Olympics. Two finalists, but no medalists, from 1972 returned: sixth-place finisher Markku Kukkoaho of Finland and seventh-place Karl Honz of West Germany. Alberto Juantorena was the favorite, ranked #1 in the world and trying to become the first man to win the 400 metres/800 metres double (outside of the 1906 Intercalated Games). His main competition was the United States team, aiming for a sixth consecutive win in the event.[6]

Antigua and Barbuda, Belize, the Netherlands Antilles, and Papua New Guinea appeared in this event for the first time. The United States made its eighteenth appearance in the event, the only nation to compete in it at every Olympic Games to that point.

The competition retained the basic four-round format from 1920. The "fastest loser" system, introduced in 1964, was applied in the first round. With 20 fewer runners than in 1972 (44 compared to 64), there were only 6 first-round heats, each scheduled to have 7 or 8 athletes but one with only 6 starters. The top five runners in each heat advanced to the quarterfinals along with the next two fastest overall. The 4 quarterfinals each had 8 runners; the top four athletes in each quarterfinal heat advanced to the semifinals, with no "fastest loser" spots. The semifinals featured 2 heats of 8 runners each. The top four runners in each semifinal heat advanced, making an eight-man final.[6][11]

These were the standing world and Olympic records (in seconds) prior to the 1976 Summer Olympics.

World record	Lee Evans (USA)	43.8	Mexico City, Mexico	18 October 1968
Olympic record	Lee Evans (USA)	43.8	Mexico City, Mexico	18 October 1968

No world or Olympic records were set during this event.

The quarterfinals were moved back up to the first day (along with the first round) for the first time since 1964.

All times are Eastern Daylight Time (UTC-4)