Its present building was designed in the Gothic Revival style by Charles Amos Cummings and Willard T. Sears, completed in 1873, and amplified by the architects Allen & Collens between 1935–1937.

The church, which was built on newly filled land in the Back Bay section of Boston, is located at 645 Boylston Street on Copley Square.

In 1773, Samuel Adams gave the signals from the Old South Meeting House for the "war whoops" that started the Boston Tea Party.

Under minister George Angier Gordon, the congregation moved from its meeting house at Washington Street to its Back Bay location in 1875, occupying the present church constructed on newly filled land.

[citation needed] The church building was designed between 1870 and 1872 by the Boston architectural firm of Cummings and Sears in the Venetian Gothic style.

The style follows the precepts of the British cultural theorist and architectural critic John Ruskin (1819–1900) as outlined in his treatise The Stones of Venice.

The congregation engaged the architectural firm of Allen & Collens to design a replacement campanile and a new chapel to be named in memory of the Reverend George Angier Gordon.

Centered above the Sanctuary on the east side of the church is a copper clad cupola surrounded by twelve ornate gothic arched windows.

The interior of Old South is exuberant yet quietly modulates the mix of rich materials: highly carved Italian cherry woodwork, limestone, stenciled plaster, and stained glass.

The interior of the chancel at the east end of the church, behind the choir, is faced by a running screen of wooden arches with quatrefoil lunettes adapted from the upper arcade of the Doge's Palace in Venice.

The walls were decorated in polychrome stenciling in shades of complex tertiary colors: a rose madder background with overlays of ochre, bay leaf green, warm gray, and persimmon, and highlights of metallic gold.

The limestone tracery of the west wall of the sanctuary, with its foliage and animals, combined with the highly carved foliated woodwork and the overhead representation of the nighttime sky was intended to echo God's creation.

The combined effect was extremely rich; at once a spiritual and sensuous experience, and in great contrast to the chaste interior of Old South Meeting House on Washington Street.

Stylistically the 1875 interior was in harmony with the Ruskinian Gothic exterior, and expressed Ruskin's ideal that it is "in art that the heart, the head, and the hand of a man come together."

Tiffany was a part of an emerging American view of design in the United States, increasingly taking fewer cues from Europe.

Similar to Tiffany's work at Mark Twain's Hartford, Connecticut home, or his design for the White House's Red Room.

The period of the building's construction was adopted, using old photographs and engravings as sources, and paint analysis to replicate original colors, the interior spaces were returned closely to their 1875 appearance.

Polychrome stenciling repeated the original palette of ochre, bay leaf green, warm gray, and persimmon with metallic gold.

The church had previously installed another Skinner organ in 1915;[5] its successful inaugural concert series featured organists William C. Hammond, Gaston Dethier, Edwin Arthur Kraft, Charles Heinroth, and T. Tertius Noble.