William Lee was born in Newport, Co. Tipperary, on December 2, 1941.  He received his early education at the Convent of Mercy National school, the Boy's National school, Newport and later at Rockwell College, Cashel.  He studied for the priesthood at St. Patrick's College, Maynooth and was ordained in 1966. 

After ordination he studied Canon Law at St. Patrick's College, Maynooth, and was awarded a Doctorate in Canon Law in 1969. 

Later in 1969 he was appointed curate in the parish of Finglas West in the archdiocese of Dublin where he ministered for two years.

On his return from Dublin, he studied Canon Law for a short period at  the Gregorian University, Rome.

He was then appointed Bursar and Professor of Philosophy at St. Patrick's College, Thurles.  While there he served on the Cork Regional Marriage Tribunal, was Chairperson of the Diocesan Catholic Marriage Advisory Council and was a member of the first National Executive of the Catholic Marriage Advisory Council in Ireland.

He was appointed President of St. Patrick's College, Thurles in 1987.

He was ordained Bishop of Waterford and Lismore on 25th July 1993.

Bishop Lee has served on the Commission for Clergy, Seminaries and Vocations and the Commission for the Laity of the Episcopal Conference and was also President of Accord.

He is currently Secretary of the Irish Episcopal Conference.

 Pope Benedict greeting Bishop Lee on a recent visit to Rome