William James was the son of Henry James (Senior) of Albany, and Mary Robertson Walsh. He had four siblings: Henry (the novelist), Garth Wilkinson, Robertson, and Alice. william became engaged to Alice Howe Gibbens on May 10, 1878; they were married on July 10. They had 5 children: Henry (born May 18, 1878), william (born June 17, 1882), Herman (born 1884, died in infancy), Margaret (born March, 1887) and Alexander (the artist) (born December 22, 1890).