Ellis has been involved in many musical organisations, especially serving as Chairman of English National Opera 2005–12 (President 2012–). He was Chair of Classical Opera from 1996 to 2009 (currently President); Chair of the National Opera Studio 2012–19; Chair of the Leeds International Piano Competition, succeeding Dame Fanny Waterman, 2015–19; Trustee of the Royal College of Music 2006–10; former Trustee of London Music Masters, Sacconi Trust and the Kathleen Ferrier Award.
