Unprecedented access to Muhammad Ali's personal archive of "audio journals" as well as interviews and testimonials from his inner circle of family and friends are used to tell the legend's life story.
| Actor | Role |
|---|---|
 Muhammad AliSelf (archive footage) | Self (archive footage) |
 Jim BrownSelf | Self |
 George ForemanSelf | Self |
| TTom JonesSelf | Self |
 Mike TysonSelf | Self |
 Muhammad Ali Jr.Self | Self |
| HHana AliSelf | Self |
| MMaryum AliSelf | Self |
| MMarvis FrazierSelf | Self |
| KKen JonesSelf | Self |
| GGene KilroySelf | Self |
| GGeorge LoisSelf | Self |
| VVerónica Porche AliSelf | Self |
 Norman TownsYoung Ali | Young Ali |
| RRahman AliSelf | Self |