Amos Fithian Garrison II was born on June 5, 1840, in Gloucester County, New Jersey, to Edmund F. Garrison and Rebecca Dare. His father was a merchant who owned $15,000 of real estate by 1850. The family lived in Gloucester County, and Garrison attended school there. By 1860, Garrison was living in Salem, New Jersey, attending school and working as a clerk in a store. In 1861, he travelled to Santa Fe, New Mexico, to work as a clerk for his uncle, who was a captain in the United States Commissary Department. He later settled in Arizona, where he established a ranch. He moved to Hermosillo, Mexico, around 1870, and he married Carmen Felix on January 8, 1871. The couple apparently had no children. He died in Hermosillo on May 16, 1880.