He received his episcopal consecration on July 14, 1984, from Cardinal Timothy Manning, with Bishops William Johnson and Manuel Moreno serving as co-consecrators.

John Paul II named Steinbock as the third bishop of the Diocese of Santa Rosa on January 27, 1987.

[1] John Paul II appointed Steinbock as the fourth bishop of the Diocese of Fresno on October 15, 1991.

In 2003, Steinbock published Ministry of Presence, a book of 100 vignettes[4] from his 21 years ministering to the poor, immigrants and gang members in East Los Angeles and skid row.

He had been diagnosed with cancer in August and had been hospitalized at St. Agnes Medical Center in Fresno due to blood clots for about a month before his death.