The buildings are essentially Neoclassical in design, and executed in a handsome light-colored brick that became popular in the second half of the 1890s. Columns and entablature frame the doorway, while egg-and-dart detailing surround the parlor-floor windows.
Peterson is perhaps best known today for his row of matching buildings on Prospect Park West, around the corner. But in 1901 he became reviled as the man who ruined "Sportsmen's Row", the stretch of 8th Avenue just off Flatbush Avenue. He did this by developing the lots north of the Montauk Club with houses that faced Plaza Street, exposing their backsides to the stately homes across 8th Avenue, where many pinnacles of Brooklyn society lived. Some members of the Montauk Club tried to fend him off by raising a subscription and buying these lots from Peterson when the plans became known. But the subscription failed; Peterson proceeded; and some of the members quit the club as a result.
By 1923, 626 6th Street was owned by James J. McCullough. McCullough had earlier married Kathryn A. Tilyou, sister of George C. Tilyou, and the two brothers-in-law became business partners and founders of Steeplechase Park in Coney Island. James and Kathryn had eight children, so even so a large house as 626 6th Street might have felt a bit tight for space. In 1923, the New York Times announced the engagement of one of their sons, Edward J. McCullough:
James McCullough is said to have invented the "shooting gallery" and operated several of these amusements in and around New York. McCullough died in 1934.