When bishop Michael Portier became the First Bishop of Mobile in 1829, he set out to build a Cathedral befitting the name. Under the architectural skills of Claude Beroujon, the cornerstone for the new Cathedral was laid in 1835. After fifteen hectic years of starting and stopping construction, the Cathedral of the Immaculate Conception was consecrated by Bishop Portier on Sunday, December 8, 1850.

The Cathedral suffered fire and has undergone modifications in the ensuing years, but it still remains the edified edifice envisioned by Bishop Portier.

The Cathedral is the official church of the Archdiocese of Mobile. The word “cathedral” comes from the Latin word “cathedra” which means throne. The Archbishop's throne or chair, is located in the sanctuary and symbolizes his governing as well as his teaching role.