[1] Walker previously served as Deputy Chief of the Defence Staff (Military Strategy and Operations) from April 2021 until June 2024.

Sponsored by the British Army as a university cadetship officer,[4] he studied at the Royal Agricultural College, graduating with a Bachelor of Science degree.

[3] Walker was commissioned into the Guards Division of the British Army as a second lieutenant (on probation) on 9 September 1990 as part of his undergraduate cadetship.

[15] He was promoted to lieutenant general and became Deputy Chief of Defence Staff (Military Strategy and Operations) on 16 April 2021.

[16] He was appointed a Knight Commander of the Order of the Bath (KCB) in the 2023 New Year Honours, thereby granted the title sir.

[22] It was announded in December 2023 that Walker had been selected to be the next Chief of the General Staff, the professional head of the British Army, and would take up the post in June 2024.

[27] Walker said there were "no winners" in Russia's invasion of Ukraine, adding that "it is an utter devastation for both sides and lost generations.