In 1903 the family moved to Calgary, Alberta, where his father served as minister at the Central Methodist Church, and then as principal of Mount Royal College from 1911.

[1] Kerby joined the Royal Naval Air Service in February 1915[1] as a probationary flight sub-lieutenant, being confirmed in his rank on 21 March.

9 (Naval) Squadron in France, where on 24 March 1917 he gained his first aerial victory, flying a Sopwith Pup, sharing in the destruction of an enemy seaplane at Wenduine.

For the great courage and initiative shown by him on many, occasions, notably on the 12th August 1917, when he attacked hostile machines returning from a raid on England.

[11] He was again appointed an acting major on 1 May,[12] and on 1 August was granted a permanent commission in the RAF with the rank of captain (flight lieutenant).

[14] He was one of the first students at the Staff College, which had only just opened under the command of Air Commodore Robert Brooke-Popham.

The Directing Staff included Air Commodore Robert Clark-Hall, Group Captain Philip Joubert de la Ferté, Wing Commanders Wilfrid Freeman and Charles Edmonds, and Squadron Leader Bertine Sutton, while Kerby's fellow students included Wing Commanders Jack Baldwin and Richard Peirse, Squadron Leaders Conway Pulford, Keith Park, Wilfred McClaughry and Charles Portal, and Flight Lieutenants Eric Betts and John Cole-Hamilton.

[17] Kerby was promoted to squadron leader on 10 October 1928,[18] before finally returning to England to be posted to the RAF Depot at Uxbridge on 6 April 1929.

[19] On 1 November he was posted to serve on the staff of the Directorate of Operations and Intelligence in the Air Ministry,[20] before finally returning to flying on 4 April 1934 as Officer Commanding No.

[24] From 5 October he was a supernumerary officer on the staff of RAF Far East,[7] and from 16 November 1936 served as Air Attaché at the British Embassy in Beijing[25] and Shanghai.

[7] Kerby retired from the RAF on 28 June 1946, retaining the rank of air vice marshal.