John Pettit Douglass was born August 10, 1825, in Jefferson County, NY, son of James Douglass and his second wife, Susannah Pettit. In youth he taught school, advancing in a few years to superintendent of schools. At age 24 he bought into a mercantile business and soon established a wholesale produce dealership in Watertown, NY. He and Curtis Noble opened a commission house in NYC and sold butter, cheese and cotton. In 1853, he married Henrietta Hughson, daughter of Levi Hughson and Elmira Tucker of Pulaski, NY. They moved to NYC about 1857 and lived there until about 1873. He served one two year term as alderman in NYC. Failing health forced him to sell his city interests and he returned to Jefferson County, buying farms to become the largest landowner in the county. He built a cheese factory and introduced Holstein-Friesien cattle. He owned the Watertown Standard newspaper. His children were well educated and traveled in Europe. The last few years of his life he lived in a hotel in Theresa, NY. He died in 1903 of a heart attack and is buried in Oakwood cemetery there.

John P. and Henrietta had five children: Curtis, Florence (died young), Henrietta (mar. Mordaunt Shipley of England), Kathleen and Daniel.