From 1971 he was organist and choirmaster at Clarendon United Methodist Church, Arlington, Virginia, where he initiated the first and longest-running series of complete performances of Handel's Messiah in the Washington DC area. He also gave the first performance of a choral and orchestral work by Gordon Shi-Wen Chin, two performances of Samuel Barber's Toccata Festiva, and several complete performances of Bach's Goldberg Variations.
He appeared as organ soloist and conductor with the National Symphony Orchestra. Other performing and conducting appearances were with the New York Philharmonic, the Minnesota Orchestra, at Aspen, the Cologne New Music Festival, Bachfest Leipzig and the Handel Festival in Halle.
He ran the education and outreach programmes for the Cathedral Choral Society and the Washington Bach Consort, and received various honours.
J Reilly Lewis died at his home in Arlington, Virginia on 9 June 2016, aged seventy-one, following a massive heart attack.