[2] Marshall was commissioned into the Royal Air Force (RAF) on 2 September 1991 with the rank of acting pilot officer.

[3] Having completed an in-service degree, he was re-graded as a pilot officer on 15 July 1994.

[1] He went on to become station commander at RAF Waddington in March 2016,[6][7] and Head of Military Operations in the Ministry of Defence in December 2018.

[9] On 22 November 2021, Marshall took up the post of Assistant Chief of Defence Staff (Operations & Commitments) in succession to Major General Charles Stickland.

[11][12] Marshall was appointed an Officer of the Order of the British Empire in the 2014 New Year Honours.