He was educated in Athlone Diocesan School and Maynooth College and was ordained a Roman Catholic priest for the diocese of Elphin on 20 June 1880.
[1] On 20 September 1887 he disappeared, leaving his clothes in a boat on Lough Ree.
He was supposed to have been drowned, which attracted great attention at the time, and had the unlooked-for result of procuring some remarkable obituary notices in the Roscommon Messenger and other papers.
The Town Board, Borough Court, and Board of Guardians all adjourned, as a mark of respect to his memory, while the Vicar-General of the diocese wrote a most sympathetic letter to his father.
With the assistance of his brother, Mr Joseph Connellan, he embarked upon the evangelisation of Ireland.