Which boxer knocked out Joe Louis in his final fight?

Rocky Marciano stopped Joe Louis in Louis’s final professional fight. The bout took place on October 26, 1951, at Madison Square Garden in New York City.

Marciano won by an eighth-round technical knockout. Louis was knocked down and rose before the count, but Marciano followed with more powerful punches, sending the former champion through the ropes. Referee Ruby Goldstein stopped the contest immediately.

The result marked a symbolic passing of the heavyweight era. Louis, once the dominant champion, was 37 and had returned to boxing partly to address serious tax debts. Marciano was 28, unbeaten, and rapidly establishing himself as the next major heavyweight star.

The wording “knocked out” is commonly used for the result, although official records describe it as a technical knockout rather than a clean knockout. Marciano later became the only heavyweight champion to retire undefeated, finishing with a 49–0 record.