In this film Robert De Niro gives a very supporting performance in this, in that he is mostly there for support. He portrays Pat Sr. the father of the troubled Pat Jr. (Bradley Cooper). The main aspect of Pat Sr.'s character is his constant attention to football games and his favorite team the Philadelphia Eagles. He is always very concerned about things that create the necessary Karma for a game victory, especially since he is always gambling on the games as well. De Niro honestly does not really get any scenes to himself, and his moments are always at least someone else especially Bradley Cooper who is almost in every scene of the film.
De Niro is weaved throughout the film in the scenes as both a helpful and hurtful factor for Pat Jr. in basically equal measure. De Niro really just takes a realistic approach with his part. He combines well the various factors that weigh on Pat Sr. when it comes to his interactions with Pat Sr.. Importantly De Niro does show the proper warmth and love in their scenes together. De Niro is very understated about it, but he does successfully portray it with a great deal of effectiveness. When Pat Sr. fights with Pat Jr. for Jr's sometime very violent behavior, De Niro does not portray it with any hatred just rather as a gut reaction from Pat Sr..
Where Jennifer Lawrence as troubled young widow Tiffany who befriend Pat Jr., and Bradley Cooper as Pat Jr. are quite diagnosed about their mental problems De Niro's Pat Sr. play really an not identified obsessive compulsive. De Niro takes mostly downplays this even partially playing it for a little bit of humor. It is not that De Niro portrays it in any sort of parody actually, instead he just sort of plays in a lighter fashion which shows it as something that most certainly affects him, but in a manner that does not seem problematic for the most part. De Niro handles it well by having it just natural part of Pat Sr. than it almost hidden as him just being too intense of a football fan.
De Niro moves through the film well in the variations of Pat Sr. caused by his problems with his son or his problems with his gambling. He is very good by hitting the randomness of it all, and realistically conveys how quickly how Pat Sr. can be trying to be friendly to his son and the next moment be chewing him out. The two biggest moments of his performance are these two pulls one being when he lashes out at Pat Jr. for supposedly messing with his Karma, and later encouraging Pat Jr. to do the right thing. Both times De Niro plays them well, they are short moment, but De Niro makes them sweet through his honest depiction of Pat Sr.
This performance by De Niro is not on the same level of his work in the 70's by any measure. It is really a lesser work from an actor that can make far more of an impact in a film than he does here. That being said though he does fulfill the role of Pat Sr. the best he can. This is not a performance that steals scenes but instead it appropriately adds to them. He is likable when he needs to be, he is unlikable when he needs to be, he is charming when he needs to be, he is mean when he needs to be. He absolutely succeeds in all aspects of the character even if that is not all that much overall it definitely is a performance I liked that adds nicely to his film.