King began his Royal Navy career on 15 May 1901.[1] He was awarded the Beaufort and Wharton testimonials in 1909 and the Ronnald Megaw memorial prize for 1909–1910.[2]
Having been promoted to the rank of Lieutenant-Commander in 1916, he succeeded Sidney Bailey as gunnery officer of HMS Erin. At the end of the First World War he became gunnery officer of HMS Warspite and was promoted to the rank of Commander in 1919.[2]
In 1936 King was appointed to command HMS Queen Elizabeth and oversaw the start of its refit the following year. He then commanded HMS Despatch from 1937 to 1938 and became a Rear-Admiral in 1938.[2]