Erik Kernan Jr. (Josh Hartnett) is a young sports reporter for a major Denver newspaper. He is frustrated that his editor is burying some of his reports on sporting events. Ralph Metz (Alan Alda), the editor, explains that Erik's stories are boring, too dry with no personality. Erik's father, dead for some time, had been a famous sports broadcaster. Erik apparently has profited from his father's name, but also has the burden of his style being compared to his father's. Because of his frustration with his editor, Erik is hoping to find other reporting work.
Erik has a 6 year old son who lives with Erik's wife, Joyce (Kathryn Morris). Joyce and Erik are separated. We learn that Erik has tried to make himself seem more important in his boy's eyes than he is by falsely claiming friendships with famous athletes.
Near the parking lot of a sports arena, three possibly drunk young men are deriding an old homeless man (Samuel L. Jackson), who calls himself "Champ" and claims to have been a professional boxer. They obviously don't believe him and force him to fight one of them. He resists but eventually fights back, showing that he really can fight. The three then gang up on him. Erik, leaving a fight he was covering at the arena, comes to Champ's aid. Eventually Erik learns that Champ was once a well regarded contender, Bob Satterfield, who had fought several famous fighters, such as Ezzard Charles and Jake LaMotta. People thought he died long ago.
At a job interview to be a sports writer for a weekly magazine, Erik commits to do a feature story on this fighter and what happened to him after he lost a humiliating major fight. If the magazine owner and editor like the piece they might hire him. Erik gets Polly (Rachel Nichols), a research assistant at the paper, to dig into old records for information about Bob Satterfield's career and family, while keeping the search secret from Erik's boss. Meanwhile, Erik meets more with Champ. He takes Champ to a relatively minor fight he is assigned to cover, and becomes impressed with the man's boxing expertise that allows Champ to predict a knockout by the underdog.
Erik contacts many of the still-living people who knew Satterfield when he was still up and coming. They are surprised to learn that Satterfield is alive, saying that they had heard he died long ago. He even gets Champ and Jake LaMotta on the phone to talk about old times. However, one contact, Satterfield's son, hangs up on him as soon as he hears Erik's name. Eventually the magazine publishes Erik's article. It is extremeky well received and is picked up by the national media. People suggest it be nominated for a Pulitzer Prize.
But the publicity brings Erik into contact with morer old timers who knew Satterfield and are pretty sure he is long dead. Eventually Erik learns that Champ is not Satterfield after all, but another lesser fighter who Satterfield defeated. Erik is faced with a moral dilemma of announcing his error or suppressing the information and bask in his "success." Erik initially makes the self-serving choice, but he does not find his success to be satisfying. Eventually he decides to tell his editors about the mistake but before he can do so he learns that he and his paper are being sued by Satterfield's son. The son is upset because he and others had long known that Champ was impersonating his father, and because Erik's story falsely said that Satterfield, Jr. and Sr. were estranged. Everyone accuses Erik of not having done due diligence in checking out Champ's authenticiy.
In the end, Satterfield, Jr. is satisfied with Erik's proposal to write another article about his error and including material about Bob Satterfield that Jr. had long wanted someone to publish. Erik discovers that his 6 year old will be proud of his father even if his father does not know the famous people he claimed to know.