Charles Webb, who has died aged 81, was the author of the 1963 novel The Graduate, which was made into the hit film that helped to define the 1960s.

Directed by Mike Nichols, the 1967 film made a star of Dustin Hoffman, playing Benjamin Braddock, a recent college graduate unsure of his future and unimpressed with the society his wealthy parents assume he will enter. When his father asks him what he is doing in the pool, he says “I’m just drifting”, and when he is asked what the point of all the hard work of getting through college was for, he says “you got me”.

Advised by his father’s partner, Mr Robinson, to sow some wild oats, Benji drifts into an affair with Mrs Robinson (Anne Bancroft), immortalised in one of the Simon and Garfunkel songs used so effectively in the film, before meeting and falling in love with the Robinsons’ daughter, Elaine (Katharine Ross). It ends with Benjamin and Elaine riding silently, in the back of a bus, to a destination neither has considered.

Webb said he based the novel on the way his wife’s family rejected him, but it also drew deeply on his own character. Although Buck Henry, who won an Oscar for co-writing the screenplay, said 85% of his work was lifted straight from the book, one line that he added cut to the core of Webb’s own life. At Benji’s graduation party, he is approached, by the pool, by a friend of his parents’ who gives him advice for his future. “I want to say just one word to you. Just one word. Plastics.”

That word described the materialism which, by 1967, mainstream culture had begun to define as empty. Webb came to that conclusion earlier. He grew up in Pasadena, California, where his father, Richard Webb, was a cardiologist and his mother, Janet (nee Farringdon), a socialite. Schooled at Chandler, the poshest private school in Los Angeles, then sent to board at the Midland school, outside Santa Barbara, he went “back east” to Williams College, graduating in 1961 with a degree in American literature and history.

While there, he met Eve Rudd, a student at nearby Bennington College, a debutante from New York. Their 1962 wedding was a traditional affair held at the elite Salisbury school in Connecticut, where her parents taught. But Charles and Eve had already decided to proceed unburdened by material goods; they returned their wedding gifts and donated the money to charities.

Moving back to California, they worked in odd jobs and lived over a bowling alley while Webb wrote The Graduate, which was published with the help of his mother, who knew an editor in New York. It received lukewarm reviews, as critics compared Benji to an older Holden Caulfield, from JD Salinger’s The Catcher in the Rye. But the film transformed it into a bestseller.

Webb had received only $20,000 for the rights and refused an additional $10,000 offered by the film’s producer after it had made millions. The couple bought a house in Los Angeles, which they immediately gave back to the estate agents; they moved to Massachusetts, buying a house they then gave to the Audubon Society, and to Hastings-on-Hudson, New York state, where their house was donated to Friends of the Earth. Both eschewed, as far as possible, inheritances from their families.

Eve, an artist, took the name Fred in solidarity with a self-help group for men with low self-esteem. For her first gallery exhibition she shaved her head and presented her paintings in the nude.

Webb’s second novel, Love, Roger (1969), received little attention, though his third, The Marriage of a Young Stockbroker (1970) was seen by some as a continuation of The Graduate, and made into a movie starring Richard Benjamin, who had played a Benji-like role in the film of Philip Roth’s Goodbye, Columbus.

The couple had two sons, whom they home-schooled. This violated California law, so they lived for years in a VW camper. “My wife and I have done a lot of things we wouldn’t have done if we were rich people. I would have been counting my money instead of educating my children,” he said in 2006.

They worked in a series of menial jobs, including as caretakers at a nudist colony in New Jersey, while Webb produced four more novels, the last of which, Booze (1979), deals with an artist who paints only oranges. It seemed a straightforward comment on Webb’s view of the creative process.

For the next two decades, Webb published nothing. “The creative process is really a defence mechanism on the part of artists ... creativity is not a romantic notion,” he explained. The family lived for three years in a motel in the city of Carpinteria, near Santa Barbara, and there Webb was reconciled with his estranged brother, Sidney, who had become a doctor like their father.

Charles and Fred divorced in 1981, in protest against the institution of marriage, but remarried in order to facilitate a move to Britain in the late 1990s, so Webb could study British accents for a novel. New Cardiff (2002) was his first book in 23 years, about a British artist whose fiance sends him an invitation to her wedding with another man. Distraught, he escapes to a small town in Vermont, sketching the locals and meeting a woman who is the opposite of his lost love.

Fred did drawings for the book. It drew good reviews; Webb’s ear for dialogue again made it an easy adaptation into a film, Hope Springs (2003), a romcom starring Colin Firth, Minnie Driver and Heather Graham. Webb donated the film rights to Dan Shelton, a performance artist who had posted himself to Tate Modern in a box.

In Robert Altman’s movie The Player, Buck Henry pitches a producer with the idea of a sequel to The Graduate, and the notion brought Webb back into the public eye in 2006. A decade earlier he had written the unpublished Gwen, in which the eponymous daughter of Benji and Elaine narrates her parents’ story: Benji works at a Kmart department store and they give away their possessions to charities. But the rights to the characters had been sold away, and belonged to a film company.

Now living in Hove, East Sussex, and owing some £30,000, he managed to sort them out and publish another sequel, Home School (2007), dealing with the Braddocks’ efforts to raise their children off grid. It failed to come close to matching expectations, but the money went to clear his debt. As ever, Webb paid little attention. “People in the arts are not allowed to live normal lives,” he said in 2006. “They either have to be super-rich, or penniless like me.”

Eve died last year. Webb is survived by his two sons, David, a performance artist who once cooked a copy of The Graduate and ate it with cranberry sauce, and John.

• Charles Richard Webb, novelist, born 9 June 1939; died 16 June 2020