Viscount Trenchard is a hereditary peer in the House of Lords. He worked for Kleinwort Benson from 1973 to 1996, as chief representative in Japan between 1980 and 1985, and as director between 1986 and 1996.
For Kleinwort Benson International, he was general manager of its Tokyo branch from 1985 to 1988, president from 1988 to 1995 and deputy chairman from 1995 to 1996. He was director of Dover Japan Inc from 1985 to 1987, of ACP Holdings Ltd from 1990 to 1994.
Trenchard was director of Robert Fleming & Co. from 1996 to 1998, and of Robert Fleming International from 1998 to 2000. He was Managing Director, Investment Banking, for Mizuho International plc from 2007 to 2012 and Senior Advisor to Mizuho Bank, Ltd from 2013 to 2014.
Trenchard was also chairman of The Dejima Fund Ltd from 2001 to 2009, from 2002 to 2008 senior advisor of Prudential Financial, and from January to December 2006 director general of the European Fund and Asset Management Association. He has been chairman of Stratton Street PCC Ltd since 2006, a director of Lotte Chemical UK Ltd since 2010 and a director of Adamas Finance Asia Ltd since 2017.
For the Royal Air Force Benevolent Fund, Trenchard was member of council and trustee from 1991 to 2003 and again from 2006 to 2013. He was also chairman from 2006 to 2013 and is deputy chairman since 2014. He has been a long-time member of council of The Japan Society since 1992 to 1993 and served in several key executive roles in the Society. He is Co-Chairman of the British-Japanese Parliamentary Group.