Answer by taking a quote from the following article:

Fonda was born in New York City, the only son of actor Henry Fonda (1905-1982) and his wife Frances Ford Seymour (1908-1950); he is the younger brother of actress Jane Fonda. He and Jane had a maternal half-sister, Frances de Villers Brokaw (1931-2008), from their mother's first marriage. Their mother committed suicide in a mental hospital when Peter, her youngest, was ten, although he did not discover the circumstances or location of her death until he was 55 years old. On his eleventh birthday, he accidentally shot himself in the stomach and nearly died.

In 1968, Fonda produced, co-wrote and starred in Easy Rider, directed by Dennis Hopper, which was Fonda's breakthrough role, and a critical and commercial success. Easy Rider is about two long-haired bikers traveling through the southwest and southern United States where they encounter intolerance and violence. Fonda played "Captain America," a charismatic, laconic man whose motorcycle jacket bore a large American flag across the back. Dennis Hopper played the garrulous "Billy". Jack Nicholson was nominated for an Academy Award for Best Supporting Actor for his turn as George Hanson, an alcoholic civil rights lawyer who rides along with them. Fonda co-wrote the screenplay with Terry Southern and Hopper.  Hopper filmed the cross-country road trip depicted almost entirely on location. Fonda had secured funding in the neighborhood of $360,000 - (largely based on the fact he knew that was the budget Roger Corman needed to make The Wild Angels).  The film was released in 1969 to international success. The guitarist and composer Robbie Robertson, of The Band, was so moved by an advance screening that he approached Fonda and tried to convince him to let him write a complete score, even though the film was nearly due for wide release. Fonda declined the offer, instead using Steppenwolf's "Born to Be Wild", Bob Dylan's "It's Alright Ma (I'm Only Bleeding)" sung by the Byrds' Roger McGuinn, and Robertson's own composition "The Weight" performed by The Band, among many other tracks. Fonda, Hopper and Southern were nominated for the Academy Award for Best Original Screenplay. The film grossed over $40 million.

What is Easy Rider?
Fonda produced, co-wrote and starred in Easy Rider,