A young woman Carr had befriended, Edie Parker, introduced Carr to her boyfriend, Jack Kerouac, then twenty-two and nearing the end of his short career as a sailor. Carr, in turn, introduced Ginsberg and Kerouac to one another – and both of them to his older friend with more first-hand experience at decadence: William Burroughs. The core of the New York Beat scene had formed, with Carr at the center. As Ginsberg put it, “Lou was the glue.”
Carr, Kerouac, Ginsberg and Burroughs explored New York’s grimier underbelly together.
In July 1944, Carr and Kerouac began talking about shipping out of New York on a Merchant Marine vessel. On August 13, 1944, Carr and Kerouac attempted, and failed, to ship out of New York to France on a merchant ship – aiming to fulfill a fantasy of walking across France in character as a Frenchman (Kerouac) and his deaf-mute friend (Carr), and hoping to be in Paris in time for the Allied liberation. Kicked off the ship by the first mate at the last minute, the two men drank together at the Beats’ regular bar, the West End. Kerouac left first, and bumped into Kammerer, who asked where Carr was. Kerouac told him.
Kammerer caught up with Carr at the West End, and the two men went for a walk, ending up in Riverside Park on Manhattan's Upper West Side.
Carr killed Krammer and served two years in the Elmira Correctional Facility in Upstate New York and was released.
He remained on good terms with his Beat friends, and served as best man when Kerouac impetuously married Joan Haverty in November 1950. Carr has sometimes been credited with providing Kerouac with a roll of teleprinter paper “pilfered” from the UP offices, on which Kerouac then wrote the entire first draft of On the Road in a 20-day marathon fueled by coffee, speed, and marijuana. The scroll was real, but Carr’s share of this first draft tale is probably a conflation of two different episodes; the 119-foot first roll, which Kerouac wrote in April 1951, was actually many different large sheets of paper trimmed down and taped together. After Kerouac finished that first version, he moved briefly into Carr's apartment on 21st Street, where he wrote a second draft in May on a roll of United Press teleprinter, and then transferred that work to individual pages for his publisher.
Carr continued to serve Kerouac as a drinking buddy, a reader and critic, reviewing early drafts of Kerouac's work and absorbing Kerouac's growing frustrations with the publishing world.
According to jazz musician David Amram, Carr remained loyal to Kerouac to the end of the older man’s life, even as Kerouac descended into alienation and alcoholism