Harry Osborn is the only son of the maniacal Norman Osborn and best friend of Peter Parker (Spider-Man) in the Marvel Comics universe. He is also a major character in Sam Raimi's Spider-Man trilogy where he is portrayed by James Franco.
Harry is a close friend of Peter Parker and the son of wealthy industrialist Norman Osborn, the chairman of Oscorp Industries. Having flunked out of numerous private schools, Harry attends New York's Midtown High School alongside Peter whilst trying to downplay his life of privilege so as not to be singled out by his classmates. While he regards Peter as his best friend, he begins to grow somewhat resentful as his father begins to praise Peter's intellect while offering his own son nothing but criticism.
Harry engages in a relationship with Mary-Jane Watson, though he knows that Peter also has a crush on her, claiming that Peter never made a move. However, Mary-Jane seems to harbour feelings towards Peter and also holds a romantic fascination with Spider-Man (she does not yet know that Peter and Spider-Man are one and the same).
After Spider-Man's final showdown with Norman, aka the Green Goblin, he returns Norman's body to Osborn Manor. Harry sees Spider-Man stood over his father's body and comes to the mistaken conclusion that Spider-Man had murdered his father. Harry vows to avenge his father and destroy Spider-Man.
Two years after the death of his father, Harry has risen to the position of CEO of Oscorp. However, his responsibilities to his company are overshadowed by his obsession with Spider-Man and a rift forms between him and Peter because he believes that Peter knows the wall-crawler's identity yet won't reveal it since he makes his living by taking photos of Spidey for the Daily Bugle.
When Doctor Octopus embarks on a crime spree across New York, he demands that Harry give him Oscorp's last remaining sample of tritium so he can complete his fusion reactor. Harry agrees to give the doctor the tritium in exchange for Spider-Man, leading to the villainous scientist attacking and capturing the wall-crawler. When Doc Ock brings Spider-Man to Osborn Manor, Harry unmasks him and is shocked to discover that the web-slinger is actually Peter Parker. Stunned by this revelation, Harry lets Peter go so that he can stop Dr. Octopus and rescue the captive Mary-Jane.
Tormented by the discovery that his best friend may be responsible for the death of his father, Harry begins to descend into madness as he begins seeing hallucinations of his father in the mirror. The apparition of Norman demands that Harry avenge him, but Harry angrily smashes the mirror, only to find a hidden door behind it. Investigating the secret door, Harry finds a laboratory where Norman had stored all of his Green Goblin gear. Staring at a vial of performance-enhancing serum, Harry realises he now has the tools he needs to kill Spider-Man himself and takes up the mantle of the new Green Goblin.
Some time after discovering that his father was the Green Goblin, Harry decides to use his father's weaponry to take revenge on Spider-Man. Dosing up on the performance enhancer that originally drove his father insane, Harry modified the Goblin's arsenal and took on the mantle of the New Goblin. He then attacked Peter one night in the middle of the street, pursuing him through alleyways and over rooftops. During the chase, Harry crashed his glider and suffered a severe blow to the head, rendering him unconscious and leaving him with partial amnesia.
When Harry awoke in hospital, he had completely forgotten about his vendetta against Spider-Man and the circumstances behind his father's death. He had reverted to a happier state of mind from before his father's death and enjoyed spending what time he could with Mary-Jane and Peter. But it would not be long before his father's ghost re-surfaced in his mind and he decided to attack Peter again, this time by sabotaging his relationship with Mary-Jane.
As the Goblin, Harry attacked Mary-Jane and blackmailed her into breaking up with Peter. Mary-Jane complied, not wishing for Harry to hurt her or Peter any further. However, Peter - under the influence of the alien symbiote that had bonded with him - later attacked Harry in his own home, throwing one of his pumpkin bombs back at him and severely scarring one side of his face. It seemed that Peter's and Harry's friendship was truly dead and buried.
Some time later, after Peter had separated himself from the malicious symbiote, Mary-Jane was kidnapped by the symbiote's new host Eddie Brock, aka Venom. With Venom working alongside Flint Marko (aka Sandman), Peter knew he couldn't save MJ on his own and turned to Harry for help. The disfigured Harry was left embittered by his last defeat and refused to help Peter, telling him to leave. However, Harry's butler Bernard told him that he had cleaned Norman's wounds on the night he had died and noticed that the wound was caused by the blade of his own Goblin Glider. Realising that Spider-Man wasn't really responsible for his father's death, Harry changed his mind and decided to make amends with Peter by helping him rescue Mary-Jane.
During the fight against Sandman and Venom, Harry is knocked off of his glider by Venom who then impales him with it. Spider-Man uses one of Harry's pumpkin bombs to defeat Venom and he and Mary-Jane then kneel beside their injured friend. Harry forgives Peter for what happened to his father and the two reconcile as Harry succumbs to his wounds.