Guilfoyle attended St. James Boys' School in San Francisco from 1914 to 1922, and St. Joseph's College in Mountain View from 1922 to 1927.
[2] In 1937, he earned a Doctor of Canon Law degree from the Catholic University of America in Washington, D.C.[1] He became a domestic prelate in 1949, and was co-founder and chaplain of the St. Thomas More Society.
[2] He received his episcopal consecration on September 21, 1950, from Archbishop John Mitty, with Bishops James Sweeney and Hugh Donohoe serving as co-consecrators.
[2] In addition to his duties as bishop, Guilfoyle served as rector of Mission San Francisco de Asís (1950-1969) and military vicar of armed forces for the Archdiocese of San Francisco and the Dioceses of Monterey-Fresno, Sacramento, Reno, and Salt Lake City.
Joh and James Howard said they were molested as altar boys by Reverend Oliver Francis O’Grady, a priest at St. Ann's Parish in Lodi, California, starting in the 1970's.