Lee Marvin plays Chino the leader of a rival biker gang named The Beetles who decide to match "wits" with Johnny (Marlon Brando) and his gang. Lee Marvin's role here isn't really a substantial one by any means as Chino comes in makes some trouble then proceeds to make more trouble by getting arrested. Marvin technically could be considered the antagonist but that's not the way he plays it. He's the rival gang leader who purposefully starts a fight with Johnny but Marvin does not have an ounce of maliciousness in his portrayal. Marvin in fact plays Chino as a bit more of an approachable sort of guy than Johnny who Brando plays with a bit of a perpetual brood. Marvin instead shows Chino doesn't care like Johnny but in a completely different way. Marvin shows Chino in not caring about much of anything, not even getting beaten up or arrested, but he intends on loving every minute of it.
Marvin quite simply is a hoot in the role as he plays the role with such a constant boisterousness. Marvin is extremely flamboyant within his performance and it completely fits his role. He commands the screen despite playing the role in such a frankly wacky fashion but he completely nails this sorta guy who is practically drunk on life despite not necessarily having had anything to drink. Marvin is incredibly entertaining in his constant bravado as Chino plays up every moment as he seems to be trying to get out every bit of fun he can get out of it. When Chino is beaten down by Johnny and technically has his pride taken from him Chino responds by saving he loves Johnny. Marvin absolutely makes you believe this reaction as he realizes Chino so perfectly as the gang member who is ready to go with almost anything because he's just going to love in anyways.
Lee Marvin effectively steals the show as he turns all of his scenes into the most memorable. Where most the other behavior of the bikers is quickly repetitive and quickly obnoxious Marvin always energizes the proceedings whenever he shows up. His performance is just a whole lot of fun in a film that is sorely lacking in it otherwise, and I think this likely where he stole the film far more than what was intended. Marvin just pretty much takes the picture as his own whenever he gets to grace the screen. The only problem I would say is there is not a whole lot of Chino to go around as the film is obviously not about him and he's only a fairly brief side show. That being said he's quite the enjoyable side show for the film and easily the highlight of it all. For a performance that was fulfilling what could have been another throwaway role, and has very limited screen time that's not too bad of an accomplishment.