On July 18, 1859, Becker was ordained a priest for the Archdiocese of Baltimore by Cardinal Costantino Naro at the Basilica of St. John Lateran in Rome.

[1] When Becker's churches were converted into barracks during the American Civil War, he moved to Emmitsburg, Maryland, to teach theology, ecclesiastical history, and Sacred Scriptures at Mount St. Mary's College.

[4] He received his episcopal consecration on August 16, 1868, at the Cathedral of the Assumption of the Blessed Virgin Mary in Baltimore from Archbishop Martin Spalding, with Bishops Richard Whelan and John McGill serving as co-consecrators.

[6] He wrote a series of articles on the idea of a Catholic university, which attracted wide attention, and was an outspoken supporter of the temperance movement.

[4] During his tenure, Becker added an episcopal residence to the Cathedral of St. John the Baptist in Savannah, which he completed with the building of spires in 1896.