BB King was hailed as one of the greatest blues musicians of all time.
His vibrato style of playing influenced a generation of rock and blues guitarists, including Eric Clapton, Mike Bloomfield and Stevie Ray Vaughan.
Rolling Stone magazine once ranked BB King in third place in its list of the 100 greatest guitarists of all time, just below Jimi Hendrix and Duane Allman.
His output crossed musical barriers, from jazz and blues to mainstream pop.
He was born Riley B King in Indianola, Mississippi, on 16 September 1925. His parents were sharecroppers and, as a young boy, he helped them work in the fields.
The family struggled. "When you live in a house that you can always peek out of and see what kind of day it is," King later said, "you're not doing so well."
The sound of his co-workers hollering the blues was his first introduction to the style of music that he was to help take from a purely black American audience into the mainstream.
He bought his first guitar when he was barely a teenager so he could play at church services. In 1947 he moved to Memphis where he busked on the streets until he found work as a radio disc jockey at station WDIA.
He was introduced as "The Beale Street Blues Boy", later shortened to BB. He also built a reputation as a guitarist in the Beale Street blues clubs.
He later said: "I've said that playing the blues is like having to be black twice."
It was while playing in one of the clubs that a fight broke out over a woman, causing a fire. After rushing out of the wooden building, he realised that he had left his guitar behind.
He risked his life by going back in to rescue his instrument. He named it after the woman whose charms had been behind the trouble: Lucille.
After making his first record in 1949, he went on to top the rhythm and blues charts two years later with Three O'Clock Blues. The song remained at number one for 17 weeks.
Many of his early recordings were produced by the legendary Sam Phillips who went on to found Sun Records.
On the strength of this success, he was able to work across the US and he performed at such venues as the Apollo Theatre in Harlem, New York. Further hits included Sweet Black Angel, Rock Me Baby and Every Day I Have the Blues.
He played more than 300 gigs on the so-called Chitlin' Circuit, the collection of performance venues in what were then racially segregated southern states where it was safe for black musicians to perform.
King said: "I have put up with more humiliation than I care to remember.
"Touring a segregated America, forever being stopped and harassed by white cops hurt you most 'cos you didn't realise the damage. You hold it in."
It was thanks to the influence of British bands such as the Yardbirds, the Animals and the Rolling Stones that white audiences, first in the UK and later in America, began to embrace the blues.
BB King began to be accepted in venues that had long been closed to black musicians. One of his more moving moments was when he was given a standing ovation by a mainly white audience at the Fillmore West theatre in San Francisco in 1968.
He later recalled that he had berated his bus driver for bringing him to the wrong venue after seeing the overwhelmingly white faces in the queues of people waiting to get in.
The same year, he made his first tour of Europe. He returned many times, becoming as popular there as at home.
He had a UK top 20 hit with The Thrill is Gone in 1969, but his most successful single came with the band U2 in 1989 with When Love Comes To Town.
In 2000 he collaborated with long-time fan, and blues purist, Eric Clapton on the album Riding with the King.
King returned to Mississippi each year to visit his numerous children from a number of relationships.
He once said: "Ladies, friends and music - without those three, I wouldn't wanna be here."
King was still touring in his 80s, having played more than 15,000 live gigs during his career.
He also made a point of playing regular concerts in prisons across the US.
King was once asked what motivated him to keep up his punishing schedule of live performances.
"I would like very much to make them happy," he replied. "I want them, when they leave the venue, to say 'I enjoyed myself'."