While Monk is often regarded as a founder of bebop, his individual style veered away from the form.
Little is known about his early life. Born in Rocky Mount, North Carolina, his family moved to New York shortly after. He began playing the piano at age 6, and while he had some formal training, Monk was essentially self-taught. He briefly toured with an evangelist in his teens, playing the church organ. He attended Stuyvesant High School, but did not graduate.
Around his late teens he began to find work playing jazz; he appears on recordings of Jerry Newman made around 1941 at Minton's, a New York club, where Monk had been hired as the house band pianist. His style at the time is described as "hard-swinging", with the addition of runs in the style of Art Tatum. In 1944 Monk made his first studio recordings with the Coleman Hawkins Quartet.
He married Nellie Smith in 1947, the same year he made his first recordings as a bandleader. In 1949 they had a son, who became the jazz drummer T.S. Monk. In 1953 they had a daughter Barbara.
In August 1951, New York City Police investigated a park car occupied with Monk and friend Bud Powell. The police found narcotics in the car. Monk refused to testify against his friend, so the police took his Cabaret card. Without it he was unable to play anywhere liquor was served. Monk spent most of the early and mid 1950s composing, recording dates, and theater and out of town gigs.
Monk worked on touring and recording throughout the 1950s and 1960s. In 1964, he appeared on the cover of Time magazine. He disappeared from the scene in the early 1970s. His last recording was made in November 1971 and he only made a limited number of appearances during the final decade of his life.
Monk's manner was idiosyncratic, even for a jazz musician. He would seldom speak, he would wear odd clothes and hats, and had an unusual percussive manner in playing piano. At times he would stop playing, leave the piano, and dance while the other musicians in the combo played.
In the documentary film Straight, No Chaser, Monk's son T.S. Monk reported that Monk was on several occasions hospitalized due to an unspecified mental illness that worsened in the late 1960's. No diagnosis was ever made public, but some have noted Monk's symptons match bipolar disorder and schizophrenia.
He died in 1982 and was interred in the Ferncliff Cemetery in Hartsdale, New York. Following his death, his music has been rediscovered by a wider audience and he is now counted alongside the likes of Miles Davis, John Coltrane and others as a major figure in the history of jazz. In 1989, Clint Eastwood produced a documentary about Monk's life and music, called Straight, No Chaser.