The modest Gothic Revival structure was built in 1847 by architect Henry Bowyer Lane, who also designed Little Trinity Anglican Church at 425 King Street East, and St. George the Martyr Church at 197 John Street (only the clock tower remains).

Designed by Henry Bowyer Lane, the Church of the Holy Trinity is approximately five storeys tall.

This style emphasizes verticality and light, which is achieved through the use of tall stained glass windows and twin turrets outlining the main entrance of the church.

The pointed arch is repeated throughout the whole building, present in the doors, windows, and Gothic vault.

Mary Lambart Swale died at the age of 25 and gave the Toronto diocese a gift of 5,000 sterling to build a church.

She requested that the church in the Gothic style, that the name be Holy Trinity, that the reading desk and pulpit not be placed as to obstruct the view of patrons, and that the pews were to be free for everyone forever.

The two towers flanking the west entrance of the church became a landmark of Toronto in the mid-nineteenth century and could be seen throughout the city.

There are emblems, symbols, and initials on crests under the eaves of the entire exterior, a unique feature of the church.

The original Eaton Centre construction plans called for the church to be demolished as well, but the parishioners successfully resisted and forced the mall's design to be changed.

The church participates as a venue in Toronto's annual Nuit Blanche, and presents a weekly series of classical, choral, and jazz concerts throughout the year, as well as a dramatization of the Christmas story every December since 1937.