In early 1917, he was elected unanimously 1st Lieutenant of the Cyclist Company and as result devoted all his spare time to Volunteer work.

By May 1917, he was sworn into the Irish Republican Brotherhood and in October, Tomás Mac Curtain appointed O'Donoghue as communications of the Cork Brigade.

O'Donoghue was a key organiser in the sensational jail-break of Captain Donnchadh Mac Niallghuis on Armistice Day 1918 and took personal responsibility for his protection.

She was head female clerk at the 6th Division Headquarters at Victoria Barracks, Cork and passed on secret British Army correspondence to him.

By March 1920, after killing a RIC Inspector, Florence was on the run and serving full-time in the Irish Republican Army.

Although O'Donoghue joined the Anti-Treaty IRA and was elected onto their army’s executive as Adjutant-General,[3] he warned of the dangers of an Irish Civil War.

[1] Following the outbreak of World War II, O'Donoghue enlisted in the Defence Forces as a private in June 1940 and quickly rose through the ranks, achieving the position of Major.

Notably, he played a key role in preventing the escape of German agent Hermann Görtz and in the recapture of former Special Branch member Jim Crofton.

O'Donoghue's ability to navigate political divisions, owing to his standing with individuals on both sides of the treaty split, enabled him to recruit several IRA veterans, including republicans, into the SIS.