From July 1934 until 1936, Harwood served on the staff of the Royal Naval War College at Greenwich (HMS President).

[2] The squadron was deployed to the South Atlantic against the German pocket battleship Admiral Graf Spee, which was attacking Allied shipping there.

In the ensuing Battle of the River Plate on 13 December, Harwood's cruisers were damaged, but so was Graf Spee, which fled to Montevideo in neutral Uruguay.

From December 1940 to April 1942, Rear-Admiral Harwood served as a Lord Commissioner of the Admiralty and Assistant Chief of Naval Staff.

[2] The command was later split, and he became Commander-in-Chief, Levant, in February 1943, with responsibility for flank support and seaborne supply of the British Eighth Army.