John G. Spencer was born in Bucks County, Pennsylvania, on June 9, 1803, the son of Amos Spencer and Anna Brown. He taught school for several years and in 1833, entered the mercantile business in Springville, Pennsylvania. In 1834, he married Elizabeth Fetter; they had four children: Arnie Ann (b. ca. 1837), Amos (b. ca. 1842), Charles Watson (b. ca. 1845), and George Franklin (b. ca. 1848). In 1840, he opened a store in Oxford Valley, which he managed until his son, Charles Watson Spencer, succeeded him in 1873. Like many other members of the Spencer family, John was a Quaker; he strongly opposed slavery and had a deep interest in politics. He died March 31, 1897, at the age of 94.
From the guide to the John G. Spencer collection, Spencer, John G. collection, 1827-1855, (William L. Clements Library, University of Michigan)