Walker was born October 2, 1864, in
Huntly,
Scotland to David Walker and Barbara Cooper. In 1868 his family immigrated to the United States. He joined the Marine Corps from
Brooklyn in October 1896, and was sent as a private to
China to fight in the Boxer Rebellion. He received the Medal of Honor for his action in Peking, China from on June 20 – July 16, 1900. In 1904 he married Mary Owens and together they lived in Pennsylvania until 1922 when he retired from the Marine Corps. They never had any children and after retirement they moved to
San Jose, California. He was an active member of
First Methodist Church, the Army and Navy Legion of Valor, the Marine Corps League, Wheaton Camp, United Spanish War Veterans of San Jose and Major Randolph T. Zane Post 344,
Veterans of Foreign Wars until his death. He was killed in an auto accident October 24, 1946 in
San Jose, California. He is buried in
Oak Hill Memorial Park San Jose, California. ==Medal of Honor citation==