On a school trip, Peter Parker, a high school senior, visits a Columbia University genetics lab, where he is bitten by a genetically engineered "super spider" that escaped containment and apparently falls ill after returning home. Meanwhile, Norman Osborn, scientist and owner of Oscorp, tries to land a major military contract. He experiments on himself with an unstable performance-enhancing chemical and goes berserk, killing his assistant.
The next morning, Peter discovers that he is no longer myopic and his body has metamorphosed into a more muscular physique. At school, he discovers that he can shoot cobwebs from his wrists and that his accelerated reflexes allow him to avoid injury during a confrontation with bully Flash Thompson. Peter discovers that he has developed superhuman strength, the ability to stick to surfaces, and an increased ability to sense danger.
Ignoring his Uncle Ben's advice that "with great power comes great responsibility," Peter considers impressing his love interest Mary Jane Watson with a car. He enters a clandestine wrestling tournament to raise money and wins his first match, but the promoter cheats him with his winnings. When a thief suddenly robs the promoter's office, Peter allows him to escape. Moments later, he discovers that Ben was killed. Peter pursues and confronts the car thief, only to realize that it was the thief he let escape. After Peter disarms him, the car thief flees but dies after falling through a window. Meanwhile, a crazed Norman disrupts a military experiment by Oscorp's corporate rival, Quest Aerospace, and kills several people.
Upon graduation, Peter begins to use his abilities to fight injustice, donning a costume and the personality of Spider-Man. J. Jonah Jameson, editor of the Daily Bugle newspaper, hires Peter as a freelance photographer, as Peter is the only person who provides clear images of Spider-Man. Norman, upon learning of Oscorp's board plans to oust him to sell the company to Quest, murders them at the Unity World's Fair. Jameson calls the mysterious assassin Green Goblin. Norman (as Green Goblin) offers Spider-Man a place by his side, but Peter refuses. They fight and Peter is injured. At Thanksgiving dinner, Peter's aunt May invites Mary Jane, Norman and his son Harry, who is Peter's best friend. During dinner, Norman sees the wound and realizes Peter's identity. Shortly after leaving, Norman attacks and hospitalizes May.
Mary Jane admits that she is in love with Spider-Man, who has rescued her numerous times, and asks Peter if Spider-Man ever asked about her. Harry, who is dating Mary Jane, arrives and presumes that she has feelings for Peter after seeing them hold hands. Devastated, Harry tells his father that Peter loves Mary Jane, and inadvertently reveals Spider-Man's greatest weakness. Norman takes Mary Jane and a Roosevelt Island trolley car full of children hostage along the Queensboro Bridge. He forces Peter to choose who he wants to save and leaves Mary Jane and the children. Peter saves Mary Jane and the streetcar, while the civilians who side with Spider-Man taunt Norman. He then grabs Peter, throws him into an abandoned building, and brutally beats him. When Norman brags about how he will later kill Mary Jane, an enraged Peter overpowers him.
Norman reveals himself to Peter, who stops attacking and apologizes but at the same time controls his glider to try to impale Peter. Warned by his spider sense, Peter dodges the attack and the glider fatally impales Norman. Norman tells Peter not to reveal his identity as the Green Goblin to Harry. After saying this, Norman dies and Peter brings Norman's body to Osborn's house, where Harry arrives and finds him standing over his father's body. Harry grabs a gun with the intention of shooting Peter, but he escapes.
At Norman's funeral, Harry vows revenge on Spider-Man, whom he holds responsible for his father's death, and claims that Peter is the entire family he has left. Mary Jane confesses to Peter that she is in love with him and kisses him. Peter, however, feels he must protect her from the unwanted attention of his enemies, so he hides his true feelings and tells Mary Jane that they can only be friends. When Peter leaves the funeral, he remembers Ben's words and accepts his new responsibility as Spider-Man.
Tobey Maguire as Peter Parker / Spider-Man:
Willem Dafoe as Norman Osborn / Green Goblin:
Kirsten Dunst as Mary Jane Watson:
James Franco as Harry Osborn:
Cliff Robertson as Ben Parker:
May Parker's husband and Peter's uncle,
Rosemary Harris as May Parker
Ben Parker's wife and Peter's aunt.
J. K. Simmons portrays J. Jonah Jameson, the grouchy publisher of the Daily Bugle
Ron Perkins portrays Mendel Stromm,
Gerry Becker and Jack Betts play board members Maximillian Fargas and Henry Balkan.
John Paxton portrays Bernard Houseman
Joe Manganiello, portrays Parker's bully Flash Thompson,
Bill Nunn, Ted Raimi and Elizabeth Banks portray Daily Bugle editor Robbie Robertson, Daily Bugle employees Ted Hoffman, and Jameson's secretary Betty Brant respectively.
Michael Papajohn appears as The Carjacker,
Bruce Campbell, cameoed as the announcer at the wrestling ring
Bonesaw McGraw, "Macho Man" Randy Savage.
Octavia Spencer staff member at Parker's wrestling match.
R&B/soul singer Macy Gray appears as herself performing at the World Unity Fair.
Lucy Lawless a punk rock girl
based on the Marvel Comics character of the same name
the first installment in the Spider-Man trilogy