The current Saint Mary church building, located on Hillhouse Avenue near Yale University, was dedicated in 1874.

In 1882, Michael J. McGivney, the Saint Mary's assistant pastor, founded the Knights of Columbus at the parish.

A separate Eastern Catholic parish of Saint Michael, part of the Ukrainian Eparchy of Stamford, also exists within New Haven.

In the summer of 1827, Irish immigrants working the Enfield Falls Canal at Windsor Locks sent to New York for a priest to tend to one of their number who had fallen grievously ill. Vicar general John Power responded.

It being Sunday, a group of Catholics requested use of a small chapel on the Long Wharf, and being refused next resorted to a barroom.

James Fitton from Hartford was delayed saying midnight Mass in 1831 when his horse gave out four miles from town and he had to walk the rest of the way.

In September 1832 James McDermot was assigned as assistant to Fitton at Hartford, but not long after was appointed to New Haven.

This also entailed mission stations at Bridgeport, Waterbury, Derby, Norwalk, Danbury, Meriden, Middletown, Goshen, Tariffville, and other places.

[3] Their Protestant neighbors were averse to doing anything to encourage "popery" and refused to allow the use of or rent and space that might be used as a gathering place.

The small frame church was scheduled to be dedicated on the Feast of the Ascension, May 8, 1834, but just prior to the ceremony, the gallery gave way and two people were killed in the collapse.

The construction of a Catholic church on Hillhouse Avenue was strongly opposed by the Protestant elite who lived in the area.

[5] From February 2019 to October 2020, the St. Mary church building was temporarily closed for emergency repairs; century-old plaster had come loose and fallen from the ceiling.

Further review of archival photographs and newspaper accounts revealed circular tondo portraits of saints in each arched bay along the naive, as well as portraits of three angels above the main altar; the Canning Company recreated these tondos, working with the parish to choose a new series of modern and historic saints to be depicted.

[9] As part of the reorganization, the Dominican Order left St. Mary's on December 1, 2021, and two diocesan priests were assigned to take over as pastor and parochial vicar.

The St. Mary Priory building would house the pastor and associate priests appointed to serve the churches in New Haven.