On April 26, 1929, Pope Pius XI appointed Father Gerald P. O’Hara Titular Bishop of Heliopolis and Auxiliary Bishop of Philadelphia. On May 20, 1929, the Most Reverend Gerald P. O’Hara was ordained a bishop. At age 34, he was the youngest bishop in the world at that time.

Bishop O’Hara was appointed by Pope Pius XI on November 16, 1935, as Bishop of Savannah. Within the first year, Bishop O’Hara established several new parishes. He petitioned Pope Pius XI to designate the diocese “Savannah-Atlanta,” in recognition of the growing importance of Atlanta. The decree was authorized on January 5, 1937. After World War II, Bishop O’Hara was made an archbishop and served as papal representative to Romania, Ireland, and England and Wales, while remaining Bishop of Savannah. Archbishop O’Hara also played a major role in establishing Catholic schools around Georgia and created the Catholic Youth Organization. The name “Diocese of Savannah” was restored to the 88 counties in south Georgia in 1956. Archbishop O’Hara resigned as Bishop of Savannah on November 11, 1959. He was appointed Titular Archbishop of Pessinus that same year and died on July 16, 1963.