Merrick Gay was born in Vermont in 1802. He was one of seven children of Daniel Gay, who built a brick factory on the White River in the northeast corner of the town of Stockbridge, Vermont, in 1832, giving the name of Gaysville to the small village. Merrick married Sarah Whitcomb in the late 1820s, thus joining together two prominent Stockbridge families. Merrick and Sarah Gay eventually had six children of their own.

In the 1840s, Merrick Gay was a prosperous Gaysville merchant, amassing an estate worth nearly $17,000 by 1850. Some time during the next decade, he also began a small woolen factory, increasing his worth to about $23,000 by 1860. As one of the most prominent Gaysville citizens, Merrick Gay helped establish the local post office, served as postmaster for thirty years, as town clerk for twenty-two years, and as a state senator for two years. He died in 1866 at the age of 64. His second son, Nelson, who had joined Gay in business in the 1850s, succeeded his father in several of these activities.