Joe Pesci received his first Oscar nomination for portraying Joey Lamotta in Raging Bull.
Pesci though overcomes any potential problems easily though. Although I can't say he steals any scenes from De Niro that would be impossible, but Pesci always manages to keep his ground in every scene with De Niro. This is certainly helped by Pesci's distinctive voice, but also by the way he realizes his character of Joey almost as well as De Niro realizes Jake. There are many similarities to the men, that both actors bring to their character showing that their brothers, and from the same background.
Pesci shows that Joey is much like Jake in that they are both very abrasive men. There is not a question what Jake is feeling that is for sure, and this is mostly true for Joey as well. Pesci brings out the emotional force just as De Niro does, showing simply the brutal nature of the characters. Pesci is great in showing how Joey is similar to Jake, without copying De Niro though, instead making the same type of character but in his own distinct way.
Pesci certianly excels in showing the similarities between Joey and Jake, but even stronger I think is Pesci careful depiction of what makes Joey different than Jake. Although hot headed himself, he is far more sensible than Jake in many ways. Because of this Pesci and De Niro have an interesting dynamic as Joey and Jake. With Jake being far more blunt and hardheaded instantly, where Pesci shows Joey is always sort of undercutting what Jake says, as well as prodding him to do what he believes is the right thing to do. There is a hostility between them because of this that both actors make natural, and true to emotional state of their characters.
A pivotal part of Pesci's performance though is Joey's relationship with Jake's wife Vicky (Cathy Moriarty). Pesci carefully creates Joey's treatment, and affection for his sister in law perfectly. It is hard to say exactly how far his affection goes for her, whether it is more than just being a good brother in law. Pesci keeps it appropriately ambiguous, making it so you can't be sure one way or the other, but for it to be enough for the very jealous Jake to take it as such without much question.
What is best in Pesci's performance though may be his two last scenes where it shows a different side of Joey, where the whole abrasive behavior of he and Jake are no longer in full front. Pesci is great in his small moment where he watches Jake lose his belt, estranged from Jake due to Jake beating Joey. The moment is great because it shows that there was a genuine love for his brother in his sadness over watching Jake lose, as well as a sense of loss sense he worked hard with Jake to win the belt as well.
His best single scene though may be when we see Joey years later still estranged becuase of what Jake did to him. This scene could have fallen flat as it is the only time we see the only Joey, but Pesci is completely convincing in showing Joey as a very different quieter Joey. His and De Niro's scene where Jake tries to ask Joey to forgive him is amazing. Pesci is great in showing how the attack changed Joey in the he quietly resists Jake, until sort of forgiving him in a very moving moment naturally showing a much softer side of the man. This scene exemplifies how well Pesci supports De Niro's great performance, something he does throughout the film, making this really a just about perfect supporting performance.