He arrived at Dalhousie University and King’s College in 1947, the year James Doull began teaching in the Classics Department.
After Harvard, Crouse moved to Trinity College, Toronto, where he was a Tutor in Divinity for three years and earned a Master of Theology (First Class Honours) in 1957.
In 1970 Crouse completed the PhD at Harvard; his dissertation was a critical edition of the De Neocosmo of Honorius Augustodunensis.
Crouse’s full-time teaching career began with an appointment as Assistant Professor of Church History and Patristics at Bishop’s University, in the Province of Quebec.
In 1990 the Institutum Patristicum Augustinianum in Rome named him Visiting Professor of Patrology, a post he took up repeatedly until 2004; he was the first non-Roman Catholic to be given this distinction.