[1] Together with the venerable St. Mary's Cathedral Basilica in Galveston, Sacred Heart serves more than 1.2 million Roman Catholics in the Archdiocese of Galveston-Houston.

[5] Because of its central location, he chose Sacred Heart Church, built in 1911, to serve as co-cathedral and installed an episcopal chair.

On March 11, 1897, Keaney purchased property facing Pierce and Fannin Streets and architect Olle J. Lorehn drew plans for a gothic-style church.

Crow, the fourth pastor of Sacred Heart, constructed a two-story, brick rectory that was completed and occupied in 1920 to replace the wooden structure.

Monsignor Jerome A. Rapp, the fifth pastor of Sacred Heart (1927–1952), oversaw much of the interior decoration of the church including acquiring statuary.

His successor, Monsignor John J. Roach, installed central heating and air-conditioning in 1953 and in 1954, expanded the parish footprint by acquiring adjacent property at Fannin and Calhoun Streets.

[citation needed] Monsignor Roach had the exteriors of the church and school refurbished in 1957, enlarged the sacristy and made other alterations in addition to constructing a new rectory.

Bishop Fiorenza took a picture of the co-cathedral model to the Vatican where he reportedly obtained approval of the design from Pope John Paul II.

[13] The exterior dome is clad in copper and capped by a gilded crucifix while the interior features an 8 ft (2.4 m) occulus depicting the Holy Spirit in stained glass.

[citation needed] The existence of the Sacred Heart Co-Cathedral does not affect the status of St. Mary's Cathedral Basilica in Galveston.

On April 2, 2008, the New Co-Cathedral of the Sacred Heart open its doors with a dedication Mass, attended by Bishops and Cardinals from across the United States and around the world.

[15] Since construction of the Co-Cathedral was completed in April 2008, Linbeck Group (the General Contractor) has been awarded numerous accolades for its work on the project.

[citation needed] The Archdiocese announced plans in late 2007 to demolish the 1922 Sacred Heart School building to provide parking for the new Co-Cathedral across San Jacinto Street.