John Fleming was born Feb. 16, 1948, in Ardpatrick, County Limerick. He obtained a baccalaureate in divinity in 1971 at St. Patrick´s College, Maynooth.
After pastoral and administrative work in Limerick, and work and studies abroad, he obtained his licentiate in canon law at the Gregorian University (1979-1981) and was reappointed diocesan secretary and later financial administrator (1981).
He served at the Irish College in Rome as director of Studies and later vice rector (1983-1993) and was appointed rector from 1993 to 2001.
He succeeds Bishop Thomas Finnegan, who submitted his resignation in August 2000 on reaching age 75.
The Diocese of Killala has a Catholic population of 38,000 in 22 parishes, and includes parts of counties Mayo and Sligo.