The diocese was established by Pope Pius XI on December 9, 1937, the same day that the Dioceses of Camden, New Jersey and Owensboro, Kentucky were established. The new Diocese of Paterson was created by taking territory formerly part of the Diocese of Newark. Bishop Thomas J. Walsh, the bishop of Newark, was made the Archbishop of a newly elevated Archdiocese of Newark the next day, December 10, 1937. One week later, Walsh's auxiliary bishop Thomas H. McLaughlin was appointed as the first bishop of Paterson, and the former parish church of St. John the Baptist in Paterson was established as the Diocesan Cathedral.