Walker joined the Royal Navy, was appointed an acting sub-lieutenant on 15 March 1901 and was confirmed in this rank the following year.
[1] He was promoted to lieutenant on 15 March 1902,[2] and in June 1902 was appointed to command the torpedo boat No.
He was promoted to the rank of Commander on 30 June 1914, in the 1914 Birthday Honours list,[6] and served as Captain of the torpedo vessel HMS Vesuvius during most of the First World War.
He ended his career as Commodore in Charge at Hong Kong 1930-1932, and retired as Rear admiral in October that year.
Following the outbreak of the Second World War, Walker re-enlisted as staff officer at the Admiralty.