Byzantine Catholics moved to the western United States from the east and in Phoenix they began to plan for a church of their own as early as 1956.

Permission was granted to acquire the property of the former St. Thomas the Apostle Antiochene Orthodox Church in 1968.

The Northridge earthquake in 1994 damaged the chancery offices of the Eparchy of Van Nuys and the Cathedral of St. Mary.

Bishop George Kuzma and his staff relocated to Phoenix and as a result St. Stephen's was named the pro-cathedral.

Bishop Thomas Olmsted served as Apostolic Administrator from 2018-2023, under appointment by Pope Francis.