 He also served as chancellor of the Archdiocese of San Antonio from 1932 to 1941.On August 1, 1941, FitzSimon was appointed the third Bishop of Amarillo by Pope Pius XII.He received his episcopal consecration on the following October 22 from Archbishop Amleto Giovanni Cicognani, with Bishops Mariano Simon Garriga and Sidney Matthew Metzger serving as co-consecrators.