Career
Educated at the Belfast Royal Academy, Girdwood was commissioned into the Cameronians (Scottish Rifles) in 1899. He served in the Second Boer War. He also served in World War I, having been appointed a Brigade Major with the Scottish Rifles Brigade in 1911.
He fought with his regiment at Gallipoli, becoming Commander of the 156th (Scottish Rifles) Brigade in Egypt and Palestine in 1916.
He was made General Officer Commanding 74th (Yeomanry) Division in Palestine and France later that year. After the War he was appointed Commander 9th Infantry Brigade and then GOC 3rd Division in 1919.
He was made Commander of Military Forces in Iraq in 1924 and GOC Bombay District of India in 1926. He was appointed Commandant of the Royal Military College Sandhurst in 1927 and GOC Northern Ireland District in 1931.
He retired in 1935.