 For schooling, he attended a local Roman Catholic school, O'Neill College in Elsternwick, Victoria and later Melbourne Technical College.He graduated from the University of Melbourne as a Bachelor of Science with first class honours in 1938, achieving a Master of Science in 1939 and a Doctor of Science in 1944 at the same university.Ennor was the first professor appointed by the new Australian National University in Canberra in 1948.