The three-time world heavyweight champion was not only a master in the ring, but also a strong advocate for human rights and racial equality in the United States.
Ali's great fights against the likes of Joe Frazier and George Foreman draw emotion and passions from fans and commentators alike, but the numbers behind his career are equally as impressive.
Here we run down some of the stand-out facts and figures of Ali's greatness.
91.8 per cent - Ali's win rate, having emerged victorious in 56 of his 61 professional fights. Three of his five defeats came in his final four bouts.
37 - Ali won 37 fights by way of knockout. He suffered just one knockout defeat - to Larry Holmes in his penultimate matchup in 1980.
3 - Victory over Leon Spinks in 1978 made him the first three-time world heavyweight champion. Only Evander Holyfield has since surpassed Ali's mark, earning heavyweight gold on four occasions.
548 - The number of professional rounds Ali fought in his career.
1,315 - Ali did not fight for over three years (1,315 days to be exact) over his refusal to be drafted for the Vietnam War. Ali was 25 at the time of his exile starting, robbing him of some of the peak years of his career.
31 - Defeat to Joe Frazier in 'The Fight of the Century' at Madison Square garden in 1971 was Ali's first professional defeat after 31 consecutive wins.
12 - Ali fought in 12 different countries, across four continents. Need a sign of how times have changed? Floyd Mayweather Jr fought all 49 of his pro bouts in the United States - and 25 of them in Las Vegas.
37 - Ali graced the cover of Sports Illustrated no fewer than 37 times. Only Michael Jordan tops him with 50 appearances.