In 1974, he petitioned and was accepted as a seminarian for the Diocese of Helena. His theological studies were at St. Thomas Seminary, Denver, Colorado. Bishop Elden Francis Curtiss ordained him as a priest for the Diocese of Helena at St. Patrick Church in Billings, Montana, on May 19, 1978.
His priestly assignments included: Associate Pastor at St. Patrick Parish in Butte (1978), Graduate Studies at Montana State University, Bozeman, with residence at Holy Rosary Parish (1980); Superintendent of Butte Central Catholic Schools and Principal of Butte Central High School (1981); Chancery with responsibilities for the Diocesan Centennial Celebration and Carroll College Faculty (1983); Pastor, St. John the Baptist Parish, Frenchtown (1984); Pastor, St. Anthony Parish, Missoula (1991); Pastor, St. Richard Parish, Columbia Falls (2005); Senior Status with residence in Missoula (2018). As a senior status priest, he traveled the United States to promote the work of Catholic Relief Services.
For the past few months of his life, Father John resided at The Auberge at Missoula Valley and at The Springs at Missoula. He died on September 22, 2021.