Tillsley was born in 1931, and was commissioned as an officer in 1956. He served variously in pastoral, youth work, training and administrative positions in Canada, the United States of America, the United Kingdom and Australia before being appointed Chief of the Staff in 1991.
Like many of his forebears and contemporaries, Tillsley is a gifted writer and communicator. He received his BA in Philosophy from the University of Western Ontario.
Tillsley became General following a triple by-pass operation in June 1992. He was elected General on 28 April 1993 on the fourth ballot. He assumed command on 9 July.
In May 1994, Commissioner Earle Maxwell (Chief of the Staff) announced the General had relinquished that office, effective immediately, following a major breakdown in his health due to a previously undetected congenital weakness of his heart. The General lives in Canada.