The first musical work for which he is remembered was his role as bassist in the trio Joseph Holbrooke, alongside guitarist Derek Bailey and drummer Tony Oxley.

In 2012, the centenary of the Titanic's sinking, Bryars made a new extended version, with film projections by Bill Morrison and Laurie Olinder, that included his four children as a low-string ensemble (viola, 2 cellos, bass) and turntablist Philip Jeck, subsequently released on GB records (BCGBCD21 2013) Another well-known early work is Jesus' Blood Never Failed Me Yet (1971), which has as its basis a recorded loop of a homeless man singing a musical fragment that the old man had improvised.

Bryars was a founding member in May 1970 of the Portsmouth Sinfonia, an orchestra whose membership consisted of performers who "embrace the full range of musical competence" – and who played popular classical works.

The ten short works were played on BBC Radio 3 without any introductory announcements, and Bryars wrote that Muñoz hoped they would appear to the listener in a similar way to the Shipping Forecast, "bemused by this fleeting and perhaps enigmatic curiosity.

He has written several pieces for dance, including Biped (1999) for Merce Cunningham, as well as works for William Forsythe, Carolyn Carlson, Edouard Lock and David Dawson.

He has written a great deal for early music performers including six books of madrigals, several works for viol consort and a collection of 54 "laude" based on a 12th century manuscript.

In 2015 he was named Transcendent Satrap, the highest honour in the Collège, a position he shares with Marcel Duchamp, Man Ray, Eugène Ionesco, Umberto Eco, and others.

It was included on the album Reflections alongside specially written pieces by other composers such as Nico Muhly, Mark-Anthony Turnage, Evelyn Glennie and Sally Beamish.