Terry Jennings was born in Eagle Rock, California on July 19, 1940. At the age of two he began to select records from his parents' collection, showing a lack of interest in the "records for young people" that they had chosen for him. He was taught by both of his parents and began playing piano duets with his mother at the age of four. By the age of 12, he was studying John Cage's Sonatas and Interludes for Prepared Piano. In junior high school Jennings was a featured clarinet soloist with the orchestra. He also made arrangements of Stravinsky piano pieces so that the orchestra would have music to play that he found interesting. During this period he worked on an opera and, one day, while visiting the Los Angeles Conservatory of Music and Art, a group of professional musicians rehearsing the Schoenberg Op. 29 Suite needed an E-flat clarinet player. Terry sight-read the part, transposing on his B-flat clarinet. He attended John Marshall High School in Los Angeles, the alma mater of composer La Monte Young, whom Jennings met in 1953. Jennings played and studied with Young and was greatly influenced by him. In 1954, at the age of 14, Jennings entered the Los Angeles Conservatory of Music and Art, where he studied saxophone with William Green. It was in 1957 that he met Dennis Johnson, another composer who was not just an influence on him, but also a great appreciator of his music. In addition to his study of composition with La Monte Young, he also studied with Robert Erickson at the San Francisco Conservatory of Music and Leonard Stein at the California Institute of the Arts.
Jennings' first serious works were composed in 1958, with his style of composition eventually developing in the direction of modal improvisations, through which his saxophone playing prompted comparison with the great Indian shahnai player Bismillah Khan and the American jazz saxophonist John Coltrane. Jennings first came to musical prominence in the late 1950s when he began to compose in the style of Young's influential early works involving sustained tones and expanded time concepts. He was introduced to the New York avant garde in 1960, when Young opened his series of concerts at Yoko Ono's loft with two programs of Jennings' music. Jennings was a part of many important new music concerts of the 1960s, both as a composer and a performer, premiering, among others, Richard Maxfield's Wind for tape and saxophone, composed as a portrait of Jennings. He worked with the James Waring Dance Company (1962) and performed and recorded with Young's Theatre of Eternal Music. Jennings' Piano Piece (1960) and String Quartet (1960) were published in An Anthology (edited by Young) in 1963, which led to their performance in England by Cornelius Cardew, John Tilbury, and others. Jennings also wrote a collection of very beautiful poems that have remained almost completely unknown outside a small circle of his closest friends. Terry Jennings died in San Pablo, California on December 11, 1981.
Jennings' music has been performed throughout the United States and Europe, including concerts in New York, Ann Arbor, Seattle, Boston, Los Angeles, Austria, Germany, and the UK.
His music has been recorded posthumously on Point Records by Jon Gibson and La Monte Young, and on Table of The Elements, featuring Jennings on soprano saxophone accompanied by John Cale on guitar. In the '80s and '90s, under the direction of Young, pianists Joseph Kubera and Michael Schumacher and cellist Charles Curtis studied the music of Jennings in depth. Curtis has become an authority on the performance practice of Jennings' work.
The New Grove Dictionary of American Music states: "With Young and Terry Riley, Jennings was involved in the earliest developments of drone-inspired, modal, repetitive music. He is best known for two piano works of 1965, Winter Trees and Winter Sun, both of which exemplify the repetitive, nonvirtuoso keyboard style he was among the first to employ; sets of phrases are played quietly in a specified order but repeated at will, in relatively free rhythm, and with liberal use of the sustaining pedal, creating a meditative mood and an understated lyricism. Jennings had a decisive influence on such composers as Harold Budd, Peter Garland, and Howard Skempton, who in the early 1970s created a body of so-called 'minimalist' keyboard music and were among the few musicians to perform his works. In later years Jennings composed works in a neo-romantic style, including the song cycle The Seasons (1975)."