The first church on this site was a small wooden hut with a thatched roof made from the reeds that gave Roseau its name - roseau means "reed" in French, the name French woodcutters gave the river, the town, and eventually the cathedral. The Kalinago people, who originally called the region Sairi, built that first structure in their own construction tradition. It survived until 1816, when a hurricane destroyed it. The replacement, built 24 years later on the same site, was soon too small. The abolition of slavery brought formerly enslaved people into the congregation - Black and white worshippers sitting together in the pews without discrimination - and the church needed to grow. What followed was an expansion program that stretched across the rest of the 19th century and into the 20th, each addition reflecting a different chapter of Dominican history.

A steeple went up in 1855. In 1865, Kalinago artisans undertook the ceiling project, cutting simaruba trees - a tropical hardwood native to the Caribbean - and transporting them from the forests northeast of Roseau. The work took three months. During this same period, a large stone pulpit was erected, and its origin is remarkable: the stone was carved by prisoners held on Devil's Island, the French penal colony in Guiana where political prisoners and serious offenders endured brutal conditions. How the carved pulpit traveled from a prison colony to a Caribbean cathedral is a question the historical record does not fully answer, but its presence in the church links Dominica to the wider network of French colonial punishment and labor. In 1873, the Chapel of St. Joseph was established at the southeast end, along with a crypt for the burial of bishops and priests.

A hurricane in 1863 caused substantial damage to the cathedral and destroyed many other churches across the island. Restoration funds came from a levy imposed on French planters - the colonial economy paying, in a sense, for the spiritual infrastructure it depended on to maintain social order. The rebuilding continued into the 20th century: stained-glass windows were added, and new stone pillars went in during 1902. A second steeple was constructed on the western end using stones salvaged from the demolished old church at Pointe Michel, finally bringing symmetry to the cathedral's facade. The spire was completed in 1916, marking the consecration of the building in its present form. The Gothic Romanesque Revival structure is built of volcanic rock - fitting for an island that is itself volcanic - with Gothic stained-glass windows in the upper sections and wooden shutters below for ventilation in the tropical heat.

The cathedral sits in southern Roseau on the banks of the Roseau River, which gave the town both its water supply and its name. To the south stands the Fort Young Hotel, built on the remains of a colonial fortification. To the northeast is the Dominica Museum. The cathedral is the seat of the Diocese of Roseau, a suffragan of the Archdiocese of Castries in Saint Lucia. From the outside, it appears modest - the volcanic stone walls are dark and solid rather than soaring. But the interior opens into a spacious, well-lit nave where a century of Caribbean craftsmanship converges: Kalinago woodwork overhead, prison-carved stone at the pulpit, and light filtering through stained glass dedicated to saints and navigators. It is a building that contains multitudes, constructed by hands from across the colonial world, standing on ground the Kalinago first named.