His birth name was John Len Chatman, although he claimed to be have been born Peter Chatman. It is commonly believed, though, that he took the name to honor of his father, Peter Chatman Sr., when he first recorded for Okeh Records in 1940. Although he performed under the name Memphis Slim for most of his career, he continued to publish songs under the name Peter Chatman.

A prolific artist, Memphis Slim ranks with the greatest blues pianists of all time. Big Bill Broonzy advised him early in his career to develop a style of his own, instead of imitating his idol, Roosevelt Sykes.

Memphis Slim took his name from Memphis, Tennessee, where he was born and raised. Memphis Slim got his start playing the blues at the Midway Café, at 357 Beale Street (southeast corner of Fourth and Beale Street's) in Memphis in 1931. After his early career in Memphis, where he emulated barrelhouse piano players like Roosevelt Sykes and Speckled Red, he moved to Chicago, Illinois and recorded for Okeh Records (as Peter Chatman & His Washboard Band) in 1940. The same year he also recorded for Bluebird Records, billed as Memphis Slim. He played piano as Big Bill Broonzy's partner until 1944. This exposure gave Slim opportunities not only in the juke joints he had been playing, but also in the "uptown" nightclubs.

After World War II Slim joined Hy-Tone Records, cutting eight tracks that were later picked up by Ping Records. Lee Egalnick's Miracle label recorded the pianist in 1947; backed by his jumping band, the House Rockers (its members usually included saxophonists Alex Atkins and Ernest Cotton), Slim recorded his classics "Lend Me Your Love" and "Rockin' the House." The next year brought the landmark "Nobody Loves Me" (better known via subsequent covers by Lowell Fulson, Big Joe Williams, and B. B. King as "Everyday I Have the Blues") and the heartbroken "Messin' Around (With the Blues)."

In 1949, Slim enjoyed an R&B number 1 with "Messin' Around". The pianist kept on label-hopping, moving from Miracle to Peacock to Premium (where he recorded the first version of the down-tempo blues "Mother Earth") to Chess to Mercury before staying put at Chicago's United Records from 1952 to 1954. This was a particularly fertile period for the pianist; he recruited his first permanent guitarist, Matt Murphy, who performed "The Come Back," "Sassy Mae," and "Memphis Slim U.S.A." At this time he also worked with the songwriter and bassman, Willie Dixon.

In all, he recorded more than 20 albums under his own name, and appeared on many more recordings as a sideman.

Slim left the United States for good in 1962. A tour of Europe, in partnership with bassist Willie Dixon a couple of years earlier, had so intrigued the pianist that he moved permanently to Paris. There he had more recording and touring possibilities, plus he was treated with greater respect than in the United States. He remained there until his death in 1988.

In the last years of his life, he teamed up with respected jazz drummer George Collier. The two toured Europe together and became friends. After Collier in August 1987, Slim appeared in public very little. Two years before his death, Slim was named a Commander in the Ordre des Arts et des Lettres by the Ministry of Culture of the Republic of France. In addition, the U.S. Senate honored Slim with the title of Ambassador-at-Large of Good Will.[3]

Memphis Slim died on 24 February 1988, of renal failure[4] in Paris, at the age of 72. During his lifetime, he cut over 500 recordings and influenced blues pianists that followed him for decades.