Johnny Cash will be mourned in circles far beyond the world of modern country music which he did so much to shape. His stature as an artist and his maverick attitude combined to make him the country star who appealed to young rock’n’roll devotees, to conventional folk audiences, to people who don’t like country and to hard-core fans alike.

He will be missed, too, by those whose causes he supported. He was the perennial champion of the underdog and it is significant that his two most commercially successful albums were recorded live in front of prison audiences: Folsom Prison (1968) and Johnny Cash at San Quentin (1969). A part-descendant of the Cherokee tribe and the son of a cotton farmer, he made regular fundraising appearances on behalf of Indian education and bankrupt rural state fairs.

Forever tagged as “the man in black”, he was often cast in his songs in the role of the outlaw cowboy, the chain-gang prisoner or a man facing some other physical or emotional plight with dignity rather than despair. Sung in his resonant baritone drawl, such numbers as I Walk the Line, Ring of Fire and Folsom Prison Blues remain among the most plangent themes that country and western music has to offer, although it was a cheerful piece of knockabout nonsense, A Boy Named Sue, that provided him with his biggest single hit.

John R. Cash was born in 1932 in Kingsland, Arkansas, the son of Ray and Carrie Cash. When he was three the family moved to Dyess, Arkansas, where they survived the 1937 Mississippi river flood, an event documented in Cash’s song of 1959, Five Feet High and Rising. He endured a tough childhood, hauling water for a road gang when he was ten and hefting huge sacks of cotton by the age of twelve. Two of his six siblings died when they were still children.

After graduating from high school in 1950, he swept floors in Detroit factories before enlisting at the age of 18 for a four-year term of duty in the US Air Force. He achieved the rank of staff sergeant, and while stationed in Germany he learnt to play the guitar and wrote his first songs. On his discharge in July 1954 he married his Texan sweetheart, Vivian Liberto, and the couple settled in Memphis, where Cash became a door-to-door salesman of electrical appliances.

In 1956, having teamed up with the guitarist Luther Perkins and the bassist Marshall Grant, Cash secured an audition at Sam Phillips’s now legendary Sun Studios. It was an opportune moment, for Phillips had just sold the rights to Elvis Presley’s unexpired Sun contract for the sum of $40,000 and could afford to lavish attention and money on new talent. Cash was an immediate success in the country market, but before the year was out he was in the pop charts too, with his own million-selling composition I Walk the Line. Its lyrics were to set the tone for his most characteristic utterances.

I keep a close watch on this heart of mine, I keep my eyes wide open all the time, I keep the ends out for the ties that bind, Because you’re mine, I walk the line.

I find it very, very easy to be true, I find myself alone when each day is through, Yes, I’ll admit that I'm a fool for you, Because you’re mine, I walk the line.

You've got a way to keep me on your side, You give me cause for love that I can’t hide, For you I know I'd even try to turn the tide, Because you're mine, I walk the line.

As sure as night is dark and day is light, I keep you on my mind both day and night, And happiness proves that I'm right, Because you're mine, I walk the line.

It was a performance from which he was, creatively speaking, never to look back. And yet the subsequent pressures of stardom led Cash by degrees into a damaging cycle of drug dependency which was to creep up on him at various stages of his life.

He needed stimulants to find the energy to cope with years of relentless touring schedules, and tranquilisers if he ever hoped to relax — “downs to get off to sleep, and ups to start you on your way”, as Paul Simon was to put it. His work suffered and by 1966 his marriage had collapsed. In October 1965 he was arrested in El Paso, attempting to cross the Mexican border with a guitar case full of pep pills. Most people assumed he was a write-off.

“I took all the drugs there are to take, and I drank,” Cash told the author Peter McCabe in May 1973. “Everybody said that Johnny Cash was through ’cause I was walkin’ around town 150 pounds. I looked like walking death.”