Ashenden was ordained at
Southwark Cathedral in 1980 and served as a
parish priest for 10 years in the
Diocese of Southwark, firstly at St James's
Bermondsey and then as vicar of
Hamsey Green in
Sanderstead. Between 1989 and 2012 he held the post of university chaplain and senior lecturer in the Department of English at the
University of Sussex where he lectured in literature and the psychology of religion. He was appointed a senior officer of the university in 1994. He convened and taught the MA programme "Monotheism and Mysticism in Critical Theology". From 1995 to 2003 he also lectured in systematic theology at the
University of Brighton. From 1991 to 2010 he was also a part time chaplain at
Roedean. He was appointed firstly as a
canon of
Chichester Cathedral in 2003, and subsequently to a further theological canonry (Bursalis Prebendary) in 2006. He was examining chaplain and Diocesan Adviser on New Age Religions to the
Bishop of Chichester. In 1998 he was a Church of England delegate to the 8th Council of the
World Council of Churches held in
Harare, Zimbabwe. He was a member of the
General Synod of the Church of England from 1995 to 2012. He has lectured in the United States, including, in 2003, as a visiting theologian for St. Mark Lutheran Church in Salem, Oregon. In 2012 he took early retirement from his university post and from 2012 to 2016 was 'house for duty' incumbent as vicar of St Martin de Gouray in
Gorey, Jersey. He was vice-chairman of the
Keston Institute during the 1980s, and a director of Aid to Russian Christians, in which role he engaged in
smuggling Bibles and medicine to the "Underground Church" in the
Soviet Union during that decade. He was a member of the
Society of the Holy Cross, and the
Little Brothers of Jesus. In 2016, Ashenden was appointed to the board of reference for the
Global Anglican Future Conference. He also joined Anglican TV Ministries as their UK correspondent. ==Resignation from Church of England positions==