Ellis, the son of the MP Thomas Edward Ellis, who had died seven months before his birth, and his wife Annie Jane (née Davies)[1] was educated at Westminster School (where he was a King's Scholar), the University College of Wales, Aberystwyth and Jesus College, Oxford.
He left to become headmaster of the County School in Rhyl, a post he held for 10 years.
[4] He served as warden of the Guild of Graduates of the University of Wales for six years, and as High Sheriff of Cardiganshire from 1944 to 1945.
[5] They had a son, Rolant, and a daughter, Marged, who, under the name Meg Elis, is a writer and activist.
[6] Ellis also made a number of contributions to the Dictionary of Welsh Biography (published by the Honourable Society of Cymmrodorion) and articles and reviews in various English- and Welsh-language journals.