James Alexander Walker was born around 1833 in Illinois to William Hammer Walker. His father was a Virginia-born “Horticulturist” who owned $40 of real estate in 1850. The family was living in Keokuk County, Iowa, in 1850, but Walker eventually settled in Mason City, Illinois. He began work as a physician, and by 1860, he owned $500 of personal property. He married Eliza Ann Harris in Mercer County, Illinois, on August 28, 1862, and they adopted a daughter named Susie sometime before 1880.
By 1870, they owned $6,000 of real estate and $4,000 of personal property. His wife Eliza died sometime in the 1880s, and Walker married Alice May Childs around 1887. They moved to San Lorenzo, California, soon afterward, and their son James was born there around 1893. By 1900, Walker was working as a real estate agent in San Lorenzo. They eventually moved to Felton, California, and purchased a house. He died in Santa Cruz, California, on February 12, 1911.