Born in Blackburn in 1978, James Weeks read Music at Queens' College, Cambridge, where he was Organ Scholar, before completing a PhD in Composition at Southampton University, studying with Michael Finnissy.

His music is regularly heard across Europe, has been broadcast on German and Dutch radio and BBC Radio 3, and is promoted by the BMIC's New Voices scheme. Recent works have been completed for Alison Balsom, Kürbis, Bloomsbury Trio, Anton Lukoszevieze, EXAUDI and The Hola, and he has been heard at festivals and halls including Purcell Room, Bridgewater Hall, City of London Festival, Dartington, Vale of Glamorgan Festival, Soundwaves Brighton, Gaudeamus and Mafra (Portugal). In February 2007 his music was the subject of a portrait concert by Kürbis Ensemble (London), in which his large-scale instrumental trilogy Schilderkonst was given its première.

Other recent major works include The Open Consort (for mixed ensembles based on 17th-century models), Stacking, Weaving, Building, Joining (for any number of players), Hototogisu (for children’s choir and piano duo) and New Day (for solo piano and ensemble). While the main focus of his recent music has been on solo and small-ensemble works (many of them variously rethinking notions of ensemble playing and working with extreme distillations of musical materials), he has also produced a steady stream of choral and vocal ensemble works and music for solo voice. Of these, Sint Lumbi, commissioned by the Choir of Gonville and Caius College, Cambridge, was released on Signum Records in 2005; he has also completed three works for the professional forces of EXAUDI. Current commissions include Finchley Children's Music Group (for their 50th anniversary season in 2008), Uroboros Ensemble and the oboist Christopher Redgate.

James' activities as a conductor are focused on contemporary repertoire, though he also specialises in early vocal music. He was appointed Musical Director of New London Chamber Choir in November 2007, having worked with them on Stravinsky's Les Noces for the Barbican's Michael Clark Company Stravinsky Project. In 2002 James founded the contemporary specialists EXAUDI Vocal Ensemble with the soprano Juliet Fraser. With them he maintains a busy concert schedule of major UK and European festivals and venues, and has released four acclaimed CDs on NMC, of Finnissy, Fox, Lutyens and Skempton. He is also Musical Director of the Orlando Chamber Choir (London), and has worked as a guest conductor with Endymion, IXION, I Fagiolini, New Music Players and Birmingham Contemporary Music Group, with whom he has recorded Howard Skempton's Chamber Concerto for NMC. He is much in demand as a choral animateur and tutor, and has led courses for Lacock and Dartington International Summer School (Monteverdi Vespers, 2006), where he will return in Summer 2008 with an all-Schütz programme. In July 2008 he will spend a week as Artistic Director of Palladium Musicum, Venice, working with young professionals on Venetian Baroque repertoire.

James is also active as an organ recitalist, pianist and writer on contemporary music, and broadcasts regularly on early and new music for BBC Radio 3. In December 2006 he gave the first-ever BMIC Cutting Edge organ recital in St John's, Smith Square, a programme of Fox, Finnissy and Feldman; also in 2006 he co-founded the ensemble Kürbis with the composer Claudia Molitor, dedicated to the performance of contemporary and experimental chamber music. The ensemble has performed in London, Cambridge (Kettle's Yard) and at Soundwaves Brighton, the latter a programme of Skempton, Cardew and Feldman, recorded for BBC Radio 3.