St. Augustine's parish was established in 1842. The cornerstone for the present church was laid in 1866 and the completed church was dedicated by Bishop McFarland on St. Patrick's Day in 1868. It became a cathedral when the Diocese of Bridgeport was established in 1953.
The edifice went through a major 4 million dollar renovation in 2003 and the capacity was expanded to 750 people. The project was finished in 2004 with new marble tiles, repainted ceilings, a new altar, and other projects. Archbishop Gabriel Montalvo, Apostolic Nuncio to the United States, celebrated the Mass. Bishop William E. Lori and 12 other bishops from around New England and New York concelebrated, in the presence of Cardinal Edward Egan of New York, and Cardinal William Keeler of Baltimore. Archbishop Daniel A. Cronin of Hartford delivered the homily.