Peter... When you said Spider-Man said no, you mean you said NO!
~ Harry discovers that Peter Parker is Spider-Man.
You don't give people hope, you take it away... now I'm gonna take away yours.
~ Green Goblin to Spider-Man right before he kidnaps Gwen Stacy.
The Green Goblin (real name Harry Osborn) is one of the two main antagonists of the 2014 film The Amazing Spider-Man 2 along with Electro.
He was portrayed by Dane DeHaan, who also portrayed Andrew Detmer in Chronicle.
Harry was a childhood friend of Peter Parker and was there for him, when his parents died. When Harry was 11, his father shipped him off to a boarding school. For his 16th birthday, his father sent him a bottle of scotch (though, it was obvious that it had in fact been sent, by an Oscorp employee). Events like these, cause Harry to resent Norman.
At one point, Harry had a fling with a French supermodel. He also began to experience symptoms of his father's illness.
Returning to New York
In 2014, the 20 year old Harry returned home, just before his dad passed away. Harry was now Oscorp's CEO and was soon reunited, with his childhood friend. He also became convinced, that the blood of Spider-Man (whom he had figured out, had gotten his powers from one of the now destroyed spiders), would be able to cure him. Knowing, that Peter had taken photos of him, Harry asked him to get in touch with Spider-Man. Later, Spider-Man appeared in Harry's home, but refused to give him his blood, regardless of what Harry offered him.
Harry became increasingly desperate, when his assistant informed him that they company had drained venom from the spiders, before destroying them. He tried to find out where it was stored, but came across information about Electro and was quickly locked out of the system. To save himself, Menken framed Harry and had him fired. Enraged, Harry sought out Electro, at Ravencroft and freed him.
Together with Electro, Harry headed back to Oscorp and took Menken hostage, while sending Electro off, to take out the city's power. Menken took Harry down into a secret area and was forced to inject Harry, with the spider venom. The venom had a violent effect on Harry. In pain, he crawled over to an Oscorp prototype exo-skeleton and glider and put it on. Harry flew to the power plant, arriving shortly after Electro's defeat. He realized that Spider-Man was Peter Parker and grabbed Gwen, attempting to throw her to her death. Harry began fighting Spider-Man, inside of the nearby clock tower, but was ultimately defeated and locked away at Ravencroft.
Months later, Harry was visited by the Gentleman, who informed Harry that he had found several suitable candidates. Harry asked him to keep it small and sent him down to the secret area, to collect weapons and equipment for the chosen candidates.
Promotional picture of the Green Goblin
Harry and Peter before there were enemies
Harry asks Spider-Man for his blood to save him for his disease
Green Goblin confronts Spider-Man for not giving him his blood
In the The Amazing Spider-Man Films, Norman has not taken the Goblin Mantle since he died before having chance to do so.
This marks the second time Harry Osborn has been a villain in a Spider-Man movie, with the first time being in Spider-Man 3.
He bears more similarity to some versions of his father like having trouble with the board of detectors and becoming the goblin as a result which happens in the Sam Raimi films and the 80's Animated Series versions of his father and being the one responsible for Gwen's death like the comic book version of his father.
Although credited as the Green Goblin, he is never referred to that name in the film.
He seems to share some mutual attraction towards Felicia, his personal assistant, as Felicity Jones says that she is the Goblin's girlfriend in an interview.