Marshall Grant, founding bassist of Johnny Cash’s original band the Tennessee Two and the singer’s longtime road manager, died Aug. 7 in Jonesboro, Ark., after suffering an aneurysm. He was 83.

According to a report in the Nashville Tennessean, Grant, who lived in Hernando, Miss., was in Arkansas to play at the Johnny Cash Festival, a charity event to fund restoration of Cash’s childhood home in Dyess, Ark.

North Carolina-born Grant was working with Roy Cash as a mechanic at Memphis’ Automobile Sales Co. in July 1954 when he was introduced to Roy’s brother John, newly arrived home from Air Force duty in Germany.

Cash, Grant and another mechanic, Luther Perkins, were soon jamming at Grant’s home. All three men played guitar; since it was determined that Cash would sing lead and play rhythm and Perkins would play lead, Grant bought a standup bass for $25 and quickly learned the instrument’s rudiments.

The trio’s primitive musical skills resulted in the “boom-chicka-boom” sound heard on such earthy Cash recordings as “Folsom Prison Blues” and “Hey, Porter,” cut for Sam Phillips’ Sun Records in 1955-58.

Grant and Perkins remained with Cash when the singer moved to Columbia Records in 1958. Two years later, the Tennessee Two became the Tennessee Three with the addition of drummer W.S. “Fluke” Holland.

The group backed Cash on many of his most famous and commercially successful recordings, including the singles “Ring of Fire” and “I Walk the Line” and the live LPs “At Folsom Prison” (No. 13 nationally in 1968) and “At San Quentin” (No. 1 in 1969).

In his 1997 autobiography, Cash said Grant and Perkins “limited me,” but he added, “We played it and sang it the way we felt it, and there’s a lot to be said for that.”

Grant, who did not drink, use drugs or smoke, loyally supported Cash onstage and wrangled the singer on the road into the ’70s. But the star’s recurring addiction to amphetamines made life “a living hell,” the bassist told biographer Michael Streissguth.

Cash fired Grant in 1980, and the bassist subsequently sued his former boss for wrongful termination and embezzlement. The action was settled out of court.

Grant went on to manage vocal group the Statler Brothers, who had been members of Cash’s touring troupe in the ’60s. He had played on the act’s 1966 breakthrough hit “Flowers on the Wall.”

He reunited with Cash at the legendary singer’s last major appearance, an April 1999 cable TV tribute; with Holland on drums, Grant supported Cash on “Folsom Prison Blues” and “I Walk the Line.” Cash died in September 2003.

Grant was portrayed by Larry Bagby in director James Mangold’s 2005 biopic “Walk the Line.” The bassist published a memoir, “I Was There When It Happened: My Life With Johnny Cash,” in 2006.

Survivors include his wife Etta.