yeppers how did you like Russell's boxing skills? I wonder who was the best fighter among the actors. I can name two, boxer/actors, Victor Mclagen who fought Jack Johnson and later won the academy award, Tony Danza, an honest to goodness puncher. But what actor? Ryan O'Neil, who was trained by Jose Torres, Robert DeNiro, Errol Flynn, Jon Voight?
Jack O'Halloran (Superman 2) fought Foreman before acting. Fred Ward from Short Cuts and Mickey Rourke were actor/boxers. Luis Santana, when he fought Terry Norris, combined the two professions in one fell swoop.
The guy who portrayed Baer was very good, obviously he watched some fight footage because he really took on Baers' mannerisms in the ring. The character was poorly drawn however as Baer in real life wasn't a scumbag like in the movie. Robert Ryan, Jack Palance, Charles Bronson and some others mentioned here were good actor-boxers. The WORST boxer portrayal in film had to be John Wayne in "The Quiet Man". Duke always threw wide looping arm punches, even as a cowboy. Interesting that no one has mentioned Sly Stallone....
Frank Hagney a sparring partner type was a Hollywood stunt man and a friend of Wayne's .He said Wayne and Gary Cooper could have been good fighters. Stallone was never a boxer. Bronson had some fights, he was around 52 when he made The Street Fighter. Palance boxed professionally,Ryan was a college champ.
Daniel Day Lewis was the best actor turned boxer. The choreographing for the fight scenes in "the boxer" were far too sophisticated for any of the usual Hollywood suspects like dinero, Stallone, Elvis, O'Neil, Bronson etc. Those guys were drilled actual sequences but no real understanding of footing or range ever came across in any of their scenes that were shot for entertainment value only. The Lewis scenes were far closer to actual boxing between real boxers. I've heard all the stories about how long these other Hollywood guys trained with champions for their art but it simply does not pass the eye test. You could teach your wife to mimic their moves just as plausibly. Not Daniel Day Lewis. Less entertaining but more like a boxer.
The worst punch I ever saw thrown was by Roger Moore. Bill Murray and Robert Mitchum threw punches like they could fight.