Harry Osborn was the son of wealthy industrialist, Norman Osborn, the original Green Goblin. He went to the same college as Peter Parker, aka Spider-Man. They were roommates for a time, during which Harry encountered occasional problems with drugs. When his father died, Harry found the body and removed the costume.
After learning that Peter was Spider-Man he donned his father's costume and proclaimed himself the Green Goblin. After destroying Peter's apartment in a battle with Spider-Man, he began seeing a psychiatrist who tied him up and became himself the Green Goblin.
Harry later suffered from amnesia, forgetting the identity of Spider-Man and both his and his father's roles as the Green Goblin. Harry later married Liz Allan, an old high school friend of Peter's and had a son, Normie.
This tranquility was shattered when the aftereffects of the Inferno crisis sundered the barrier between Harry's conscious and subconscious minds. Once again, he remembered being the Green Goblin - and his irrational hatred of Spider-Man. Harry had convinced himself that Peter resented the Osborns' "stable family life" due to never having been wanted by his own parents or guardians, when in fact the complete opposite was true. His sanity was shattered, he declared that their next confrontation would be their final one, and only one of them would be alive at the end. To ensure that he was the victor, Harry researched his father's chemical notes, hoping to recreate the original Goblin's superhuman strength. Harry made his own modifications to the formula, and upon ingesting it, it proved better than he had dreamed. The formula had made him stronger than both Spider-Man and his father. Now a physical match for Spider-Man, Harry planned his final revenge.
Harry took to stalking Peter Parker on his Goblin Glider, claiming that there was no law against just soaring around town in a colorful costume, and taunting Peter that someday he would destroy him, but he relished keeping Peter in suspense in the meantime. After weeks of this, Peter finally lost his nerve and struck at Harry, only to be sent flying when Harry hit back, demonstrating his new strength. Harry rocketed away, taunting Spider-Man's inability to stop him.
Not long after, Harry held a prestigious dinner at his townhouse, inviting many of his father's old business associates. However, it was actually a trap, and Harry had planted explosives throughout the townhouse, which he planned to detonate, thus destroying everybody who had slighted the Osborns.
Spider-Man, worrying the most, dropped in to investigate, only to be confronted by Harry as the Goblin. The two former friends engaged in a dangerous battle, which ended when Harry injected Peter with a drug that left him immobile, but still alive. However, even as he celebrated over his victory, he realized that Mary Jane and his son Normie were also in the townhouse, and that the explosives would detonate in thirty seconds. Despite protestations that he was not a hero, Peter convinced Harry to use his damaged glider to get the two to safety. After rescuing Normie and Mary Jane, Harry finally returned to his senses and realized that he had left Peter to die. Harry rescued Peter from the explosion just in time. However, as his friends thanked him, he suddenly collapsed. The Goblin Formula was damaged by the explosion, and while it had increased his strength, it was also lethally poisoning him. Paramedics were called, but Harry died en route to the hospital. With his final words, he apologized to Peter, and confirmed that despite everything, they were still, and would always be, best friends.
Before his "death", Harry Osborn persuaded the Chameleon to create two robots who would appear to be Peter Parker's dead parents in an effort to get Peter to tell them who Spider-Man really was. Harry already knew Spider-Man's identity but wanted to mess with Peter's head so he convinced Chameleon that Parker, due to all the photos he had taken, was sure to know Spider-Man's identity. When Spider-Man discovered the fraud, he went briefly insane over the disappointment of losing his parents again.
However, the goblin formula that saved his father life after being impaled by his own goblin glider, also saved Harry's life by giving him the same abilities. Norman Osborn returned to his son's life and paid Mysterio to fake Harry's death and sent his son to Europe. Divorced from Liz and Harry others, he returned from a years-long stay in a European rehab. He had no memory of being the Green Goblin, nor of Peter Parker's alter-ego. Harry was now the owner of a chain of cafes based on his old college hangout, the Coffee Bean and, while he considered Peter his best friend, he hated Spider-Man with a vengeance. He was dating Lily Hollister, daughter of New York District Attorney Bill Hollister.
Menace, a new Green Goblin-themed villain, battled Norman Osborn and was infuriated by Norman stating that all he cared about was killing Spider-Man. Norman called Harry, who recognized from Norman's distorted voice that Norman the he was wearing the Goblin suit, which horrified and disgusted Harry. Harry angrily confronted his father who wanted Harry to follow in his legacy and become a greater man. The confused Harry was saved by Spider-Man. Spider-Man, wanting to beat Norman senseless, stopped when he saw an area of Human Testing. Harry was thought to be the one responsible for the atrocious acts although he attempted to plead innocent. Harry later stated that he wanted to talk to Peter who moments earlier had been kissed by Lily, while leaving with a mysterious canister labeled "Prometheus X-90".
Prometheus X-90 was developed as a a successful cure for Mark Raxton's condition as Molten Man. Furthermore, the only human test subject was Charlie Weiderman, the short-lived second Molten Man, and the only person whom the serum could be tested on. After the cure was administered, Liz finally forgave Harry, and gave him back the wedding ring, which she originally claimed she lost.
Renting out all of Liberty Island, Harry took Lily to the island. On top of the Statue of Liberty, he got down on one knee and appeared to propose to her. Lily however rejected Harry's proposal as she was not sure as to were their relationship would lead, which surprised Harry. Harry later went to Lily's place to check up on her, and as he entered the room he was surprised to discover Lily wearing what appeared to be clothes belonging to Menace.
She found a hidden door in his closet and found an old journal of his. She began giving him a hard time about whining so much about his father. Harry thought her behavior was because she was sick. She continued to tell him she uncovered one of Norman's secret rooms in the journal. This explained why she kissed Peter after the Thunderbolts attacked; he had almost found the secret trigger to open the room. When she had first gone in, she found all of the Goblin's equipment along with some experiments. Knocking over some chemicals, she absorbed them and was now able to transform at will. She explained that she discovered Menace's attacks against her father gave him more public support. She also told him that she accepted his marriage proposal. After their talk, Harry entered one of his father's weapons caches, taking a glider, a pair of Goblin gloves, and a dart gun containing an unknown chemical. In the midst of a battle between Menace and Spider-man, he confronted and shot her with that chemical, which was a type of antidote that reverted her back to her human form. He saved Spider-Man from the crowd and left. Lily was imprisoned but escaped later leaving Harry's ring and a note. This caused Harry to sink into alcoholism, but he was eventually saved by Carlie Cooper.
Following the events of the Skrull Invasion, Norman Osborn was placed in charge of the H.A.M.M.E.R. organization, and formed his own team of Avengers.
Norman approaches Harry with the offer of a job within his organization. Harry declines, but after getting a visit from Lily, who revealed to him that she was pregnant, he accepts. Norman welcomes him into Avengers Tower, wanting to make his son part of the "American Son" project. However, Harry is shown to have an ulterior motive, based on his need to protect Lily and his child, disabling the camera in his room and sneaking off. He finds a cure for Lilly's Goblin Serum that would be safe for her and the baby, but she pushes him away, revealing that it was all a ruse to make Harry become American Son, whom Norman would eventually have die in a tragedy to increase sympathy for Norman and the Dark Avengers. She also reveals that the baby is not Harry's but in fact Norman's. In retalliation to this news, Harry dons the American Son armor and fights against his father and spares Peter from his father.
During the battle, Norman declares that Harry is no longer his son, and that he has bred a better child to replace the failure Harry. After further taunts from Norman, Harry lashes out and defeats his father, declaring "I was never your son!" When Harry has the option to kill Norman, Spider-Man goads him to decapitate Norman, as his healing factor may repair a blow to the head. Spider-Man states that by killing Norman, he would "become the son Norman always wanted." Harry backs down, and walks away from Norman Osborn forever.
Harry is then see in a psychiatrist's office, claiming he is getting over the effects of a medical treatment he received. The doctor offers to prescribe him oxycodone, a nod to Harry's past drug abuse, but it is not revealed if Harry takes the prescription.
After the events of American Son, he's moved out from his penthouse apartment, and is currently staying in Peter Parker's old room at Aunt May's. He's also secretly dating Peter's cousin, Ames. After Aunt May was corrupted by Miser Negative, Harry was forced to move out again and moves in with Mary Jane Watson.
After Norman Osborn's fall, the American Son armor was stolen whom authorities believed to be Harry Osborn, but have no true link to peg him to it other than the fact that the suit can only be used by someone with an Osborn Lineage. Harry was later visited by Gabriel Stacy who shoots him in anger for believing that Norman gave him a better life. After looking through one of Norman's journals; which explains many things that were kept secret including Gabriel's birth, Harry creates a new American Son armor for himself (based off a spare Iron Patriot and American Son armors). Harry then seeks help from a Frontline reporter named Norah, as he believes Gabriel to be incredibly unstable and planning to kill Norman from the Raft. It's discovered that Gabriel commits crimes while his 'American Son' persona undoes the damage Gabriel had caused, who identifies itself as the part of Gabriel that recognizes that what he is doing is wrong. Norman had later revealed to Harry that when he perfected the American Son formula he had removed any traces of the Goblin serum in his blood and injected the American Son formula in Gabriel and his sister; while it cured them both of the severe side-effects of the Goblin Serum, it left Gabriel more unstable and initially caused his other persona to emerge.
After an intense psychological battle, Gabriel appears to get the upper hand and proceeds with his plan. Gabriel overheard a planned ambush by a police squad and proceeds to attack them, before he can do any real damage however, he is stopped by Spider-Man. Later, after kidnapping Norah and luring Harry to a vacant warehouse, Gabriel made another attempt on Harry's life. Harry manages to get into the warehouse and begins to fight Gabriel, while attempting to convince him that Norman is nothing but pure evil. Gabriel ignores him and continues to attack his brother; only for Harry to deactivate the American Son armor via remote. Gabriel and Harry are then caught in an insuing blaze as a result of the fight, but are saved by Spider-Man. Gabriel was then seen in a psychiatric hospital then recieving a package; containing the American Son helmet and a note from Norman. Gabriel reads the note saying that Norman loves and misses him. Afterward, Norah visits Harry in his coffee shop, and notices a bottle of oxycodone in Harry's things. Troubled by what she finds Norah concludes that Harry has a drug problem and resolves to help him through it.
Carlie, Peter meet Harry and MJ at the Coffee Bean when all of a sudden Lily bursts through the wall, followed by an attacking team of super-villains. MJ and Harry try to help Lily, who's gone into labor, but they are interrupted by Doc Ock! Spider-man saves the both and Lily son and examines the baby's DNA and finds it identical to Harry's. Harry is inspired by Spider-man to raise the baby and start a new life as a father. He names the baby Stanley. On Halloween night Harry is preparing to move out with the baby and meets ex-convict Vin and reveals he considers Norman a deity and says that one he will take the baby. After Vin shows them the Goblin tattoo Harry attacks with a taser and violently beats him up.
Months later, Harry is shown living in Seattle, Washington with his son, Stanley. He has completely changed his appearance, having shaved his head and grown a beard.
- In Ultimate Spider-Man voiced by Matt Lanter. He is portrayed as Peter Parker's best friend and classmate at Midtown High. In the pilot episode "Great Power", Harry is badly injured by Klaw when he tries to protect Peter and Mary Jane Watson from the Frightful Four. In the fourth episode, Harry, jealous of Peter's new friends (Spider-Man's teammates' alter egos), throws a huge party that is crashed by Venom. After Venom's defeat, a fragment of the symbiote is captured by Harry. In the episode "Back in Black", Harry bonds with the Venom symbiote (resembling Spider-Man's Black Suit) in an attempt to one-up Spider-Man, winning over everyone in the city, loving the new Spider-Man, even J. Jonah Jameson (although he still hated the original Spider-Man). But eventually, the symbiote's personality takes over and it attempts to destroy Spider-Man once again. Spider-Man electrocuted and seemingly disintegrated the symbiote, freeing Harry.
However, the symbiote managed to survive and some of it was still on Harry. Harry returned as Venom in the episode "Venomous", in which Harry has no memory of being Venom, and Spider-Man tried to help him without exposing his identity to his teammates. Eventually, Spider-Man created an anti-venom that cured Harry and supposedly defeated Venom for good, but returned in "Rise of the Green Goblin".
- In Spider-Man the Game Harry takes on the role of the Green Goblin and investigates a plan to take over Oscorp and fights some of Spider-Man's Enemies as well as a new unknown Green Goblin that has a deeper voice.
- In the Spider-Man 3 video game Harry assumes the identity of the New Goblin to take out Peter as a boss and later assists Peter in dealing with Sandman and Venom as a playable character. He is also a downloadable character on Xbox 360. In the limited edition of the game for the PlayStation 3, he is unlockable and is downloadable for the normal version as well.
- Harry Osborn's New Goblin persona appears in Spider-Man: Friend or Foe voiced again by Josh Keaton. Similar to Spider-Man, Green Goblin and Doctor Octopus, he resembles his movie counterpart. He assists Spider-Man early in the game and is the last unlockable character when the game is completed for the first time. He has an easy-going, friendly personality in contrast to his cold demeanor in the movies.