A native of Caribou, Fr. 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 at Holy Rosary Church in Caribou. Fr. 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 of 1996, in addition to his duties at St. Ann, he was appointed pastor of St. Mary Parish in Orono. In June of 1997, Fr. Nadeau was named pastor of St. Ann Parish in Bradley while continuing as pastor of St. Ann on Indian Island. In June of 2000, Fr. Nadeau was named pastor, in solidum with Fr. Claude Albert, of St. Ignatius Parish and Holy Family Parish, both in Sanford, and Notre Dame Parish in Springvale (the three churches now comprise St. Thérèse of Lisieux Parish in Sanford). In June of 2008, Fr.Nadeau was appointed administrator of St. Paul the Apostle Parish in Bangor and, in May of 2010, he became pastor of the parish where he served until his appointment as pastor of Prince of Peace Parish in Lewiston in July of 2016. In May of 2017, in addition to his duties at Prince of Peace, Fr. Nadeau was also appointed pastor of Holy Trinity Parish in Lisbon Falls and Our Lady of the Rosary Parish in Sabattus.
Fr. Nadeau was recently a parochial vicar of Stella Maris Parish in Bucksport, St. Joseph Parish in Ellsworth, and Parish of the Transfiguration of the Lord in Bar Harbor.