That all changed when Norman, while doing tests involving experiments unfinished by Mendel Stromm, had a compound explode in his face. Norman breathed in the gas, resulting in his insanity and estrangement from Harry. Norman later became the original Green Goblin, until a stray blast from his Goblin cannon caused Norman to revert to his original self, with no recollection of his Goblin escapades.

It was around this time that Harry entered Empire State University. There he met his long time friends Peter Parker, Flash Thompson and Mary Jane Watson. Harry was dating Gwen Stacy, at the time of his enrollment, but their relationship fell through. Harry later dated Mary Jane, whose rejection caused Harry to start taking drugs. It was only with Peter's help that Harry eliminated his addiction.

It was around this time that Norman became the Green Goblin again, and during a single battle both Gwen and Norman lost their lives. In actuality Norman fled to Europe, but Harry thinking Norman was dead, blamed Spider-Man for the death of his father. Harry fought Spider-Man many times, until he was locked away to get psychiatric help for his mental instabilities. Later Harry's psychiatrist Dr. Barton Hamilton became fascinated with the Goblin legacy himself, causing Hamilton to become the third Green Goblin.

Harry later won the battle for his sanity, and he took over control of Osborn Industries, and married Liz Allen, a long time friend of his. A while later Liz gave birth to Normie, named after his grandfather. Years later, Harry began having sanity trouble once again and Harry snapped and became the Green Goblin once again, this time using an advanced strength serum.

With Spider-Man at his mercy, Harry's sanity returned, and Harry lost his life saving Peter's. Harry's plan for Peter's destruction did not end there though, as he was revealed to be the mastermind behind the so-called return of Peter's parents, the kidnapping of little Normie for subjection to the Goblin strength serum and having his untested, new Goblin weaponry found by Daily Bugle intern Phil Urich creating a heroic Green Goblin. Unlike his father, Harry will not be brought back from the dead like his father Norman, as it was the Goblin serum that killed him.

About a year after Harry's death, Daily Bugle reporter Ben Urich wrote a book titled, Legacy of Evil. Harry's son, Normie was kidnapped in order to subject him to the Goblin serum. Spider-Man saved Normie, not knowing that the serum that Normie would have been the same one that killed Harry. A short while after that Harry's father Norman returned, and murdered the Spider-Clone, Ben Reilly. It was also thought that Norman died then also until he returned and took over control of Osborn Industries. A few months after that, a fifth Green Goblin appeared and kinapped Normie. Spider-Man saved Normie, but was being hunted for a murder committed by Norman, he was framed for. A computer program created through books and momentos of Harry was created, giving life to a digital Harry Osborn.

Powers and Abilities: Harry possesses a great hatred for Spider-Man, and has super-human strength, pumpkin bombs and a more advanced Goblin Glider.

Animated Appearences:
                              The Spider Slayer
                              Return of the Spider Slayers
                              The Hobgoblin, part one
                              The Hobgoblin, part two
                              The Incidious Six
                              Battle of Incidious Six
                              Morbius
                              Enter the Punisher
                              Duel of the Hunters
                              Blade the Vampire Hunter
                              The Immortal Vampire
                              Skriek of the Vulture
                              The Final Nightmare
                              Doctor Strange
                              Enter the Green Goblin
                              Framed
                              The Man Without Fear
                              The Ultimate Slayer
                              Goblin War
                              Turning Point
                              Guilty
                              The Return of Kraven
                              The Awakening
                              The Vampire Queen
                              The Return of the Green Goblin
                              The Wedding
                              Farwell, Spider-Man