Thelonious Sphere Monk III was born on December 27, 1949, in New York City, the son of the pianist and composer Thelonious Monk. Known in the family as Toot, he received his first drum set from Art Blakey at the age of 15, according to Wikipedia, and took lessons from Max Roach. His first public appearance as a drummer was with his father on a 1970 television show, and he then toured with his father's group for about five years, until the elder Monk's retirement in the mid-1970s.

Alongside the touring he took other jazz dates. He is the drummer on the tenor saxophonist Paul Jeffrey's albums Family (Mainstream, 1972) and Watershed (Mainstream, 1973), and he plays congas and percussion, credited as Toot Monk, on Louis Hayes's Breath of Life (Muse, recorded in 1974). After his father stopped performing he turned to the R&B that had caught his generation, first touring with a fusion group called Natural Essence, and also played in Paul Jeffrey's big band, before forming his own band with his sister Barbara.

That band, billed simply as T.S. Monk, was a disco-funk and R&B act on Mirage Records, an Atlantic-distributed label, and this part of his career was not jazz. Its first album, House of Music (1980), was produced by the songwriter Sandy Linzer, with Monk on drums, in the arrangements and as lead singer on the single "Bon Bon Vie (Gimme the Good Life)," released in August 1980. The record reached number 63 on the Billboard Hot 100 in March 1981, number 11 on the Hot Soul Singles chart and number 13 on the dance/disco chart, and it also charted in Britain; "Candidate for Love" was the follow-up. Two more albums followed, More of the Good Life (1981) and Human (1982, produced by the singer Eric Mercury), with his sister, known as Boo Boo, and the singer Yvonne Fletcher among the vocalists, but the early chart success was not repeated. Monk and Mercury made a further album as Merc and Monk in 1985. His father died in February 1982, and his sister Barbara died of cancer in 1984.

In 1986 he helped establish the Thelonious Monk Institute of Jazz, a Washington, D.C. educational organization in his father's name that funds music scholarships and runs an annual international jazz competition; his official biography and a 2003 interview describe him as its chairman, and in 2019 the institute was renamed the Herbie Hancock Institute of Jazz after its longtime board chairman, Herbie Hancock. Working with the institute drew him back to jazz. He played in Clifford Jordan's big band and with the pianist Walter Davis Jr., and by October 1991 he had a working sextet, with Don Sickler on trumpet and as arranger, Bobby Porcelli on alto saxophone, Willie Williams on tenor saxophone, Ronnie Mathews on piano and James Genus on bass. That month it recorded Take One at Rudy Van Gelder's studio in Englewood Cliffs, New Jersey, his first jazz album as a leader and the first of three for Blue Note, followed by Changing of the Guard (1993) and The Charm (1995). The sextet's repertoire was lesser-known hard bop from the 1950s and 1960s, by writers such as Kenny Dorham, Hank Mobley, Clifford Jordan and Tommy Turrentine, alongside a few of his father's pieces.

For what would have been his father's 80th birthday he assembled Monk on Monk (N2K, recorded February 1997), an all-Thelonious program built around an expanded sextet with a long list of guests, among them Herbie Hancock, Wayne Shorter, Arturo Sandoval, Dianne Reeves, Nnenna Freelon, Roy Hargrove, Wallace Roney, Clark Terry, Ron Carter, Christian McBride and Geri Allen. It won the first annual New York Jazz Awards recording of the year and, according to his biography, DownBeat's readers' poll album of the year. In December 1996 and January 1998 he and Tom Carter guided two ABC television specials, A Celebration of America's Music, presented with the institute and hosted by Bill Cosby, on which he played his father's "'Round Midnight" with Herbie Hancock, Pat Metheny and Nnenna Freelon.

His later albums were Crosstalk (N-Coded Music, 1999), on which he sang on record for the first time in more than fifteen years, and Higher Ground (2003) on his own Thelonious Records, which mixes straight-ahead jazz with funk and smoother material. He is also credited as a producer on archival releases from his father's estate, including At Carnegie Hall with John Coltrane (Blue Note, 2005) and Palo Alto (Impulse!, 2020). In 2017, the centennial of his father's birth, he toured a Monk on Monk program, and his most recent album, Two Continents One Groove (Storyville, 2022), is a live set by the sextet recorded in Harlem in 2014 and in Bern, Switzerland, in 2016.

As a drummer Monk is a driving, swinging hard bop player; the critic Scott Yanow likened his sound to Tony Williams. His sextet's approach is repertory work with a point of view, reviving obscure small-group tunes from the Blue Note and Riverside era in Sickler's arrangements, and reviewers of Changing of the Guard and The Charm praised it as a cohesive working band rather than a tribute act. Listeners compared the group to Art Blakey's Jazz Messengers, and Monk has said he stepped into the opening left by Blakey's death in 1990. His own account of his career is of a musician who refused to choose between jazz and the funk, R&B and pop he grew up on, which is why the catalog runs from the 1980 dance hit to Monk on Monk; his R&B and disco work lies outside the jazz subgenre taxonomy, so the tags above describe only his jazz recordings. His chief influences were his father, whose music he has recorded and presented since the early 1990s, and his teachers and mentors Max Roach and Blakey.