Lenny is born in Cookstown, County Tyrone, on September 27, 1928. He is educated at St. Patrick’s Grammar School, Armagh, and St. Patrick’s College, Maynooth. He is ordained priest for the Archdiocese of Armagh on June 21, 1953. Pursuing his studies in ancient classes and canon law in Maynooth and the Dunboyne Institute, in July 1955 he is named secretary to Cardinal John D’Alton, Primate of Ireland, and upon his death in 1963, proceeds in the same position with his successor, Cardinal William Conway.
Lenny is appointed parish priest in Mullavilly in 1972. Less than two years later he is named coadjutor bishop of Armagh, receiving his episcopal consecration with the titular see of Rotdon from Cardinal Conway on June 16, 1974. Financial secretary to the Bishops’ Financial and General Purposes Committee, upon Conway’s death, he becomes vicar capitular of the archdiocese until Tomás Ó Fiaich is named his successor.
Lenny is a well known canonist and it is he who transfers a major relic of Saint Oliver Plunkett from Downside Abbey to Ireland in 1975, and is presently preserved in Oldcastle, County Meath, Plunkett’s birthplace.
A man of great charity and deep disposition, Lenny experiences great opposition from members of the Protestant community of Mullavilly, refusing to leave the village despite threats he receives. His bungalow is maliciously set on fire and he dies at the early age of forty nine on July 16, 1978, the fourth anniversary of his episcopal consecration, from injuries received complicated by a heart attack. Dressed in chasuble and mitre, he is laid to rest in a simple solid oak coffin following the celebration of a Funeral Mass celebrated at St. Patrick’s Cathedral in Armagh, presided by Archbishop Ó Fiaich which sees the participation of thousands.