A native of Caribou, Father Nadeau earned a bachelor’s degree in sociology from the University of Southern Maine and completed his clerical studies at The Catholic University of America in Washington, D.C. On May 18, 1991, he was ordained to the priesthood by Bishop Joseph J. Gerry, OSB, at Holy Rosary Church in Caribou.
Father Nadeau’s first assignment was as a parochial vicar at Holy Family Parish in Lewiston, where he served until being named pastor of St. Ann Parish on Indian Island in June of 1995.
In July 1996, in addition to his duties at St. Ann, he was appointed pastor of
St. Mary Parish in Orono.
In June 1997, Father Nadeau was named pastor of St. Ann Parish in Bradley while continuing as pastor of
St. Ann on Indian Island.
In June 2000, Father Nadeau was named pastor, in solidum with the Rev. Claude Albert, of St. Ignatius Parish and Holy Family Parish, both in Sanford, and Notre Dame Parish in Springvale.
In June 2008, Nadeau was appointed administrator of St. Paul the Apostle Parish in Bangor. In May 2010, he became pastor of St. Paul the Apostle Parish.