From: PBS http://www.pbs.org/wgbh/amex/reagan/peopleevents/pande02.html On March 30, 1981, John Hinckley Jr. set out to win actress Jodie Foster's heart. As "the greatest love offering in the history of the world," the 25-year-old attempted to assassinate Ronald Reagan outside the Washington Hilton hotel. Though flanked by administration members, police officers, and Secret Service agents, Reagan was shot under the left arm. The bullet malfunctioned and failed to explode on impact, seriously wounding but not killing Reagan. The youngest of three children, Hinckley was born in Ardmore, Oklahoma, on May 29, 1955. The family moved several times, first to Texas, then to Colorado. Like Reagan's mother, Hinckley's mother also belonged to the Disciples of Christ; his father became a born-again Christian in 1977. A well-adjusted, privileged child, as a teenager Hinckley became withdrawn and obsessed with public figures, including John Lennon. In 1976 Hinckley left home for Hollywood, hoping to become a famous songwriter. In Hollywood, Hinckley saw Martin Scorsese's film "Taxi Driver" at least 15 times. A confirmed loner, he apparently identified strongly with the Robert DeNiro character Travis Bickle. In the film, Travis is infatuated with Cybill Shepherd's Betsy, a political campaign worker who rejects him after he takes her to see a porn film. To regain Betsy's attention, Bickle plans, but fails, to assassinate the candidate she works for. Bickle then shifts gears, obsessively devoting himself to protecting 12-year-old prostitute Iris, played by Foster. He decides to shoot Iris' pimp, thereby ensuring his status as a hero to Iris and the media. Screenwriter Paul Schrader based his portrayal of Travis on Arthur Bremer, the would-be assassin of George Wallace whose diaries equate political assassination with celebrity and revenge against impotence and invisibility. Consciously or not, Hinckley began to emulate Bickle, accumulating an arsenal of weapons and fixating on Jodie Foster. Foster would not be his target, but his inspiration: To "rescue" her, he began to stalk Jimmy Carter during the 1979 presidential campaign. Following his arrest for possession of firearms in the Nashville airport, where he had followed Carter to a campaign stop, Hinckley's parents sent their youngest son to psychiatrist John Hopper. Hinckley was already taking prescribed antidepressants, and Hopper didn't detect mental illness; instead, he attributed Hinckley's problems to "emotional immaturity," recommending the Hinckleys cut off their son financially, which they did. In May 1980, after reading that Foster was enrolled at Yale University, Hinckley began to criss-cross the country regularly to be near her. Establishing contact with her twice, he believed the relationship would go nowhere unless he could catch Foster's attention with a grand gesture. So, on March 30, 1981, in broad daylight, among a crowd of supporters and onlookers, Hinckley fired six bullets at Reagan in the space of three seconds, hitting Reagan, a police officer and a Secret Service agent, and seriously wounding Press Secretary James Brady. Upon his arrest, Hinckley asked the arresting officers if news of the shooting would preempt that night's Academy Awards broadcast. (It did; the ceremony aired the next night, the Academy paying its respects to one of its own.) Hinckley's trial in 1982 ended in a not-guilty verdict, by reason of insanity. The assassination attempt won him notoriety and media attention, and also led to legislation limiting the use of the insanity plea in several states. Twelve years and two administrations later, President Clinton signed the Brady Bill, which requires a waiting period and background check on all handguns purchased through licensed dealers. The bill has come under fire both from supporters, who believe its requirements are too lenient, and opponents, who say it infringes on the constitutional right to bear arms. Confined to St. Elizabeth's Hospital in Washington, DC, since his trial, Hinckley's obsession with Foster continued. In 1999, however, after significant progress in his psychiatric treatment, Hinckley was allowed to leave the grounds for supervised visits. In April 2000 he won the right to unsupervised furloughs. The following month these rights were revoked when guards found in his room a smuggled book about Jodie Foster. (He is banned from having any material about the star.) He has always seemed aware of his motivations, even immediately after the shooting. In 1981 he told "Newsweek": "The line dividing life and art can be invisible. After seeing enough hypnotizing movies and reading enough magical books, a fantasy life develops which can either be harmless or quite dangerous." NOTE: The question is WHy did John Hinckley, Jr. shoot Ronald Reagan. . .questions regarding the weapon and ammo are an entirely different matter and not relavant to answering this question. Perhaps it should be submitted as its own question?

He did it for attention, from Foster and the media. He wanted to be famous. The article says he was an aspiring songwriter. Everyone ignored him so he created this fantasy that would give him what he craved: celebrity. To that end he succeeded, although along the way he began to have a second motive: he wanted Jodie Foster to like him. That he wasn't successful with. Deranged creature, I say.

Because he is a raving lunatic