Until the early 1990s, its economy was largely based on shipbuilding, and it is due in part to this that the town experienced a population increase of 295% in just over a decade.

Mortier Bay also served a strategic role during World War II, and was the site selected to evacuate the Royal Family and regroup the British Navy in the event of German invasion of Britain.

In more recent years, the church has received much attention from the news when a family of illegal immigrants from Israel resided there as a place of sanctuary.

Alexi and Angela Portnoy and their five children (the three youngest of whom were born in Canada) stayed in the church's basement for a total of 962 days while seeking citizenship status.

[15] By 2018, it was recognized that the region exhibited significant unemployment; further, the potential workforce was not sufficient to support shipyard and aquaculture expansions envisioned in subsequent years.

[20] The Marystown Co-operative shipyard opened in 1939 was destroyed by fire in 1941; originally committed to building fishing trawlers, it was converted to minesweeper construction for World War II.

[21]: 3  The Marystown Shipyard was established by the Newfoundland government in 1959 for the construction of longliners, "motor-powered decked vessels ranging from 35 to 65 feet in length.

[23]: 79  Ownership left Canada when the American company Friede Goldman Ltd. bought the facility in 1998, and remained in American hands when ownership changed again in 2002 to Kiewit Offshore Services Ltd.[19] By 2019, the shipyard had been idle for four years and was acquired by Marbase Marystown Inc. (usually just Marbase), under a 20-year lease with the intention of establishing a service hub supporting regional aquaculture, the first of its kind in Canada.

[24] In 2019, Marbase Cleanerfish Ltd., began work on a commercial lumpfish hatchery in Marystown, with an anticipated customer base of Atlantic salmon farm operators.

[27] In November 2011, provincial government-appointed auditors backed up claims by OCI that they were losing millions of dollars each year operating the fish plant.

[29] Despite being in a province reporting one of the highest obesity rates in Canada,[30] Marystown has sport enthusiasts in disciplines including softball, soccer, swimming, track and field and hockey.