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.[20] William became engaged to Alice Howe Gibbens on May 10, 1878; they were married on July 10. They had 5 children: Henry (May 18, 1879 – 1947), William (June 17, 1882 – 1961), Herman (1884, died in infancy), Margaret (March 1887 – 1950) and Alexander (December 22, 1890 – 1946).
Most of William James's ancestors arrived in America from Scotland or Ireland in the 18th century. Many of them settled in eastern New York or New Jersey. All of James's ancestors were Protestant, well educated, and of character. Within their communities, they worked as farmers, merchants, and traders who were all heavily involved with their church. The last ancestor to arrive in America was William James's paternal grandfather also named William James. He came to America from Ballyjamesduff, County Cavan, Ireland in 1789 when he was 18 years old. There is suspicion that he fled to America because his family tried to force him into the ministry. After traveling to America with no money left, he found a job at a store as a clerk. After continuously working, he was able to own the store himself. As he traveled west to find more job opportunities, he was involved in various jobs such as the salt industry and the Erie Canal project. After being a significant worker in the Erie Canal project and helping Albany become a major center of trade, he then became the first vice-president of the Albany Savings Bank. William James (grandfather) went from being a poor Irish immigrant to one of the richest men in New York. After his death, his son Henry James inherited his fortune and lived in Europe and the United States searching for the meaning of life.
Of James' five children, two—Margaret and Alexander—are known to have had children. Descendants of Alexander are still living.
