Coulter was born in Norwich, Connecticut, to William and Hanna Coulter. He worked in an architect's office in New York City starting at 16, while a night student at Cooper Institute. When he arrived in Saranac Lake in 1896, he had fifteen years experience in architectural work. His firm sent him north for his health and to help James Aspinwall, nephew of Dr. Edward L. Trudeau, design additions to the Adirondack Cottage Sanitorium that Trudeau had started in 1884. Within five years, he was working on Swiss chalet style Moss Ledge and rustic Camp Pinebrook on Upper Saranac Lake, the latter for New York Governor Levi P. Morton, and Knollwood Club on Lower Saranac Lake. According to a 1900 newspaper account, his plans had generated more than $600,000 worth of work and kept an "army of workmen" busy.
Gilborn, Craig. Adirondack Camps: Homes Away from Home, 1850-1950. Blue Mountain Lake, NY: Adirondack Museum; Syracuse: Syracuse University Press, 2000.