Green Goblin made his first appearance in The Amazing Spider-Man #14 (July 1964).
Norman Osborn, the son of industrialist Ambrose Osborn, was born in New Haven, Connecticut. Although Ambrose was a brilliant student in the fields of science, he was also an alcoholic who lost control of his company and was abusive toward his family. In one incident, Ambrose locked Norman in one of the Osborn family's empty estates in an attempt to toughen him. It was in that darkened mansion that Norman felt haunted by a "green, goblin-like" creature that was "waiting to pounce on him." All of these events had a severe impact on Norman, planting the seeds of the megalomaniac he would eventually become. Norman would stop at nothing to regain the wealth that his father had lost.
In college, where he studies chemistry and electrical engineering, Norman Osborn meets his sweetheart Emily, gets married, and eventually has a son whom he names Harry. In his adulthood, he co-founds a major firm with his former professor Mendel Stromm called Oscorp Industries, of which he is owner and president. However, Emily becomes ill and dies when Harry is barely a year old. This tragedy pushes Norman Osborn to work harder, leading him to emotionally neglect Harry. Hoping to gain more control of Oscorp Industries, Norman accuses Stromm of embezzlement and has him arrested. Norman Osborn then searches Stromm's possessions, discovering an experimental strength/intelligence enhancement formula. When Osborn attempts to create the serum, it turns green and explodes in his face. The accident greatly increases his intelligence and physical abilities, but also drives him to destructive insanity.
Osborn adopts the bizarre identity of the Green Goblin with the goal of becoming boss of the city's organized crime. He intends to cement his position by defeating Spider-Man. As the Green Goblin, he would bedevil Spider-Man many times but fail to achieve his goal. Stromm soon returns and attempts revenge with an army of robots, but apparently dies of a heart attack after Osborn tries to shoot him through the window. Osborn discovers that college student Peter Parker, a classmate of Harry's, is Spider-Man after exposing Spider-Man to a gas that weakens his spider-sense with the aid of a gang of ordinary crooks, and allows him to be observed. Osborn captures Parker after knocking him out with an asphyxiation grenade, catching him off-guard at home and concerned for Aunt May. The Green Goblin bound Peter with a steel rope and took him to his waterfront base. He then ties him to a steel chair with the intention of torturing Peter with suspense, revealing his identity to the world, and killing Peter while he is completely helpless and at his mercy. He reveals his true identity and origin to Peter, who stalls Osborn long enough to free one hand. Seeing this, The Green Goblin releases Spider-Man for what he intends to be their climactic battle. Spider-Man defeats Osborn, who loses his memory after being knocked into a mass of electrical wires, and destroys the Goblin costume in the resulting fire.
Osborn is troubled by repressed memories of the Green Goblin and Spider-Man. A presentation on supervillains by NYPD Captain George Stacy restores Osborn's memory, but after a brief return to his Green Goblin persona, in which he abducts Parker's friends and threatens Parker's elderly Aunt May, he is exposed to one of his own "psychedelic bombs", inducing another amnesia spell. In The Amazing Spider-Man #96, Osborn stumbles upon an old Green Goblin hideout which again restores his memory. The Goblin battles Spider-Man in this and the following two issues, until Spider-Man leads Osborn to see his son Harry Osborn hospitalized, overdosed on drugs. The shock causes Osborn's amnesia to return yet again.
In issue #121 (June 1973), his memory having been regained, the Green Goblin throws Parker's love, Gwen Stacy, from a tower of either the Brooklyn Bridge (as depicted in the art) or the George Washington Bridge (as given in the text). She dies during Spider-Man's rescue attempt; a note on the letters page of issue #125 states: "It saddens us to say that the whiplash effect she underwent when Spidey's webbing stopped her so suddenly was, in fact, what killed her." The following issue, the Goblin appears to accidentally kill himself in the ensuing battle with Spider-Man when he is impaled by his Glider.
Years after Gwen's death, it is revealed that Osborn had a one-night stand with Gwen after she's overwhelmed by his charisma which, in turn, leads to her pregnancy with his twin children, Gabriel and Sarah. Osborn thus has three motives for killing Gwen; revenge against Spider-Man, to prevent her talking of their affair and creating a scandal, and to take their children to raise by himself thus becoming his ideal heirs. The only person who knew of their liaison and the existence of their children was Mary Jane Watson, who despises Osborn for his immoral behaviors long before discovering he is the villainous Green Goblin.
Green Goblin will be portrayed by Chris Cooper in the 2014 live-action film [The Amazing Spider-Man 2](movie:508593).