Casting
Before Andrew Garfield was cast as Spider-Man, other actors were considered for the role, including Michael Angarano, Drake Bell, Jamie Bell, Frank Dillane, Alden Ehrenreich, Josh Hutcherson, Aaron Johnson, Joe Jonas, Logan Lerman and Anton Yelchin. On July 1, 2010, it was announced that the role would go to Garfield, who said he calmed his anxiety about getting the part by pretending he was auditioning for a Spider-Man short film made by his friends. The film's director, Marc Webb, said that Garfield brought humor, emotional weight and physicality to the role. Garfield and Emma Stone were screen-tested together, and Webb said there was instant chemistry between them; they began dating while shooting the film.
Garfield described Peter as someone he can relate to, and said the character had been an important influence on him since he was a young boy. To prepare for the role, he studied the movements of both athletes and spiders, and incorporated spider-like movements into his performance of Peter, even when the character is not wearing his Spider-Man suit. Garfield practiced yoga and Pilates in order to be as flexible as possible. He said the physical training for the role was demanding and exhausting; he had three different stunt doubles during filming. Garfield admitted to shedding a tear when he first wore the Spider-Man costume, and that he tried to imagine a "better" actor in the suit, because seeing himself as Spider-Man did not make sense to him. He said the suit was uncomfortable and that he was not allowed to wear anything underneath except underwear, because it was skintight.
Webb described The Amazing Spider-Man as "a story about a kid who grows up looking for his father and finds himself." Both Webb and Garfield described Peter as an outsider, with Webb noting that in the early Spider-Man comics, his outsider status was defined by him being a nerdy "science whiz". Webb said that because the idea of "what a nerd is" has changed, and because "nerds" are now "running the world", a challenge of the film was how to define Peter's outsider status in a contemporary context. Garfield tried to capture how Peter "copes with the feelings of being an underdog, his confusions and his self-doubt" in an attempt to bring "a certain empathy and sensitivity to his character that explains how it helps him become the hero". He said that Peter goes through normal struggles that most people experience, and described him as "a very inspiring, aspirational character that symbolizes goodness—and how difficult it is to be good". Garfield called Peter's Spider-Man costume a "protective layer" which gives him a powerful anonymity, allowing him to become witty and "get away with anything." Garfield compared the costume to the anonymity of the Internet.
In September 2010, it was reported that Sony was casting two female lead roles, leading to speculation that both Mary Jane Watson and Gwen Stacy would appear in the film. However, The Wrap reported in November that Mary Jane was never in the script. Candidates for the role of Gwen included Dianna Agron, Lily Collins, Georgina Haig, Ophelia Lovibond, Dominique McElligott, Imogen Poots and Mia Wasikowska. By early October, Emma Stone had been chosen for the role, due in large part to her chemistry with Garfield. Stone was unfamiliar with the Spider-Man comics, and educated herself in preparation for the role. She described Gwen as "a daddy's girl" who is very responsible and protective of her family. She said Gwen offers Peter stability and "a family unit not marred with parental loss". Stone said she wanted to interpret the character in her own way, but hoped her performance would please fans of the comics.
By mid-October 2010, Rhys Ifans was confirmed for the role of Curt Connors / Lizard; Michael Fassbender was also considered for the role. Webb has stated that Connors is not a traditional villain, while Ifans has claimed he does not qualify as a villain at all. Ifans described him as a flawed and "broken" man who attempts to help others and himself but makes a bad decision. He compared Connors to Dr. Jekyll, and viewed his transformation into the Lizard as an experience of great euphoria and hubris, similar to that of a drug addict. When preparing for the role, Ifans purposely did not read many of the Spider-Man comics. When designing the Lizard, Webb chose not to give him a lizard snout, as he wanted him to appear human as well as monstrous, and be able to convey emotions.
In November, Denis Leary accepted the role of George Stacy, and Martin Sheen was confirmed for the role of Uncle Ben. Sheen described Ben as a surrogate father for Peter, and Webb praised Sheen for bringing a "benevolent authority" to the role. Webb sought to portray Ben as a blue-collar man, whose outlook on life was different from the science-inclined Peter. Webb found it interesting to explore the differences between Peter and his aunt and uncle.
Sally Field said she took the role of Aunt May as a favor to her friend Laura Ziskin, because she knew it would be Ziskin's last film (Ziskin died in 2011). Webb praised Field for bringing "genuine affection" to the role. Irrfan Khan said he was offered the role of Rajit Ratha after appearing in the television drama In Treatment. Webb was a fan of Khan after watching the series, along with Khan's films The Namesake and The Warrior. Khan said his sons were excited about the role and insisted he take it.