His tenure was also touched by scandal, with a drunk driving arrest and failure to properly handle sexual abuse cases by clergy.

Because of World War II, he was placed on an accelerated path to ordination and was ordained a priest on June 18, 1946, while only 24 years old, by Archbishop John Gregory Murray.

Only there for the summer, when the fall arrived he was assigned to Saint Thomas Academy where he served as an instructor of Latin and religion.

[4] As headmaster, he oversaw the 1965 move of the academy from sharing a campus with the College of Saint Thomas to its own location in Mendota Heights.

[8] Roach was appointed to succeed Leo Binz as Archbishop of Saint Paul and Minneapolis on May 21, 1975, and was installed on July 16, 1975.

[13][14] During the drafting process, President Ronald Reagan involved himself, appealing to Holy See for a letter that would distance itself from the Nuclear Freeze campaign.

[20][a] George Casey, a Jesuit priest and former chaplain to a group for gay Catholics, had offered $20 to anyone who would hit Roach with a pie.

The archdiocese also started a support group for gay and lesbian persons wishing to remain celibate.

His license was suspended for 90 days; during that time, he was limited to driving only for official clerical business between Tuesday and Sunday, as well as the court-required alcohol education program.

[1]: 341–343  Roach oversaw the 1987 merger and affiliation agreement between the College of Saint Thomas and seminary, which until that point had been separate institutions with adjacent campuses.

[1]: 326 His tenure as archbishop was also marred by his poor handling of the cases of sexual abuse by clergy, which was seen as too lenient.

[16] In 2000, the University of St. Thomas changed the name of Albertus Magnus Hall to the John R. Roach Center for Liberal Arts in recognition of his 20 years of service as chairman of the St. Thomas board of trustees, after a $9.8 million ($17.3 million in 2023) renovation to the 1947 Collegiate Gothic building.