•
Kevin Spacey as Eugene Simonet, Trevor's social studies teacher, and an emotionally and physically scarred man. As a teenager, he suffered abuse from his father (including lighting him on fire) and still has burns visible on his face and torso. He begins the film as a shy recluse, self-conscious about his deformities, but eventually, he enters a relationship with Trevor's mother Arlene, and overcomes his fears. He sets an assignment for Trevor's class, asking them to change the world for the better. He is changed significantly from the novel, where there was an African-American man named Reuben St. Clair who had been injured in the Vietnam War. •
Helen Hunt as Arlene McKinney, Trevor's mother, a recovering alcoholic. She works two jobs in Las Vegas, one as a cocktail waitress and the other as a change attendant in a casino. She is given a second chance by her son when he sets her up with his teacher. •
Haley Joel Osment as Trevor McKinney, Arlene's son and Eugene's student. He creates a plan for "paying forward" favors as a social studies project. He not only affects the life of his struggling single mother, but sets in motion an unprecedented wave of human kindness which grows into a national phenomenon. •
Jay Mohr as Chris Chandler, a reporter who traces the "pay it forward" movement from Los Angeles back to Trevor. He interviews Trevor and writes a magazine column about the movement after Trevor's death. •
James Caviezel as Jerry, a homeless drug addict whom Trevor attempts to help as part of the "pay it forward" movement. Although Trevor believes his attempts have failed once Jerry relapses into drug use, Jerry eventually pays it forward by saving a woman who is about to kill herself by jumping off a bridge. •
Jon Bon Jovi as Ricky McKinney, Trevor's abusive and alcoholic father who has left the family. Arlene often allows him to return to the family despite the abuse; however, she learns throughout the film to reject him and protect Trevor and herself from violence. •
Angie Dickinson as Grace, Arlene's mother and Trevor's maternal grandmother. Although she was a negligent parent to Arlene, almost forcing them to live on the street, Arlene eventually forgives her as part of the "pay it forward" movement. •
Marc Donato as Adam, Trevor's friend who has been bullied his whole life at school. Trevor pays it forward to him by preventing him from being bullied; however, Trevor is fatally stabbed in the process. •
David Ramsey also stars as Sidney Parker, also involved in the "pay it forward" movement, as does Gary Werntz (director
Mimi Leder's real-life husband) as Mr. Thorsen.
Kathleen Wilhoite also stars as Bonnie, Arlene's sponsor and mentor. ==Production==