Crowther taught criminal and constitutional law at Exeter College, Oxford, in 1952–55. He was ordained deacon in 1956 and priest the following year, serving as curate at St. Philip and St. James' Church, Oxford, in 1956–58. After a preaching tour in the United States and a period (1959–64) as a collegechaplain at the University of California, Los Angeles, he became dean of St Cyprian's Cathedral, Kimberley, in South Africa in September 1964,[5][6] and then its diocesan bishop in 1965. Crowther was consecrated bishop in Cape Town on 14 November, and he was formally enthroned in St. Cyprian's Cathedral on 29 November 1965. Two years later he was expelled from the country for his opposition to apartheid. In 1970 he returned to California as assistant bishop and obtained a doctorate.
^"Our Companion Diocese", The Bishop's Newsletter, Vol. XXV, No. 6 (21 November 1965), p. 4. This newsletter was published by the Episcopal Diocese of Western Michigan, which at the time was a companion diocese of the Diocese of Kimberley and Kuruman.