Haynes was born in the United States in Haynesville, Claiborne Parish, in far northern Louisiana. He spent several years in Venezuela and attended an unnamed university. In 1956, Haynes was serving in the US military and stationed with a unit in Scotland; he decided to stay after his Service ended.

In 1962, Haynes co-founded the International Writers Conference with John Calder and Sonia Orwell.

in 1963 Haynes and Calder and Kenneth Tynan created an International Drama Conference which ended in a scandal, a nude young women being involved in an happening.

In 1966, Haynes relocated to London in the middle of the "swinging 60s". He became deeply involved in the underground cultural scene, co-founding the alternative paper International Times, known as "I.T.", together with Barry Miles, John Hopkins, and others.

In September 1967, Haynes co-founded the Drury Lane Arts Lab space for mixed-media. It closed in late 1969. In 1969, he co-launched with william Levy, Germaine Greer and Heathcote Williams Suck newspaper in Amsterdam to promote sexual freedom; it was also distributed in the United Kingdom. The first issue contained a long and unrestrainedly descriptive erotic poem attributed to W. H. Auden and an explicit photo of Germaine Greer.

In 1968 Haynes co-founded Videoheads with Jack Henry Moore in London.

In 1969, Haynes moved to Paris, where he taught Media Studies and Sexual Politics for 30 years at the University of Paris. He frequently held open house dinner parties on Sundays in Paris, and published an irregular newsletter about his life and times. In addition he has written an autobiographical memoir, titled Thanks for Coming. He frequently attends annual arts festivals such as the Edinburgh Festivals.

In 1970, He created and directed the Wet Dream Festival in Amsterdam.

At Christmas 2009, Haynes and his open house parties were featured in British television advertisements for multinational foods company Nestlé: "When the coffee and 'After Eight' mints come out, Jim's always got a story to tell."

Haynes had a heart attack in August 2011 on his way from Paris to the Edinburgh Festival, but he recovered. His newsletter is to be found on his website.

2016 Haynes was invited to be a living exhibit at Victoria and Albert museum in London in their exhibit about London in the 1960s.

2017 Haynes was awarded an honorary PhD from Edinburgh Napier University.