He carried through the establishment of Pobalscoil Chloich Cheannfhaola in 1973, becoming its first Principal, and with his staff he made it a successful school. His last appointment before elevation to the Episcopate was as a curate in Stranorlar.
In November 2009, Bishop Hegarty expressed concern after 17 priests in the Derry diocese were found to have child sexual abuse allegations filed against them.[5]
In 2010 the Belfast Telegraph and other media outlets reported that Bishop Hegarty was a named defendant in a civil legal action concerning the alleged abuse of a young girl by a priest of the Derry diocese. Bishop Hegarty made a statement to the press asserting that no diocesan funds had been used to compensate the victim.[6]
On 7 November 2011, he issued a statement saying that, having been diagnosed with "a condition which is, unfortunately, irreversible and progressive", he had submitted his resignation because he was no longer able to fulfill his role as diocesan bishop.[7][8] The Holy See announced on 23 November 2011 that his resignation had been accepted.[9]
He was succeeded by Donal McKeown in 2014 and Bishop Hegarty died on 20 September 2019.