After a full career in the Army, which culminated in the appointment of Commandant of the Royal Military Academy Sandhurst, Tim Toyne Sewell became Director of Goodenough College in 1995. He became the founder Chairman of the Benjamin Britten International Violin Competition in 2002 and of the Kyiv Festival in 2003.

General Toyne Sewell is also a governor of Haileybury and chairman of Lambrook Haileybury School. He is on the boards of Queen Mary, University of London; The Bill Marshall Memorial Trust; The Medical College of St Bartholomew's Hospital Trust; Barts and the London NHS Trust Fundraising Planning Committee; and The Royal Overseas League. He was chairman of the Executive Committee of Disability Sport England from 1999-2000 and remains a patron. He was appointed a Deputy Lieutenant of Greater London in 2000.