In a memorandum sent by General Sir John Maxwell to the then British Prime Minister, Herbet Asquith, the following description was provided for Michael O'Hanrahan:

This man was employed at the office of the Headquarters of the Irish Volunteers. He was one of the most active members of that body, took part in all their parades and was a constant associate with the leaders of the rebellion. He was arrested in uniform and armed, and there had been heavy fighting and casualties amongst the British troops in the neighbourhood of the place where this man with others surrendered. He was an officer in the rebel army.

Michael O'Hanrahan was tried by Field General Courts Martial on 3 May 1916. The proceedings are contained in the PRO document WO 71/357.

Court Martial Proceedings

The members of the courts martial were Brigadier-General C.G. Blackader (President), Lieutenant-Colonel G. German and Lieutenant-Colonel W.J. Kent.

To the charge of " ... did take part in an armed rebellion and in the waging of war against His Majesty the King, such act being of such a nature as to be calculated to be prejudicial to the Defence of the Realm and being done with the intension and for the purpose of assisting the enemy."

The 1st witness was Major J.A. Armstrong who stated

I was present at St. Patrick's Park on 30 April. The British troops were fired upon and there were several casualties. The fire came from the neighbourhood of Jacob's Factory. The same day a surrender was arranged. I saw the surrender being arranged by Mr. MacDonagh. Over 100 men arrived from Jacob's Factory as a result of the surrender and another large body arrived from the same direction as a result of the surrender. The accused belonged to one of the parties. He was in uniform and armed. After his removel to Richmond Barracks, he said that he was an officer.

When cross-examined by the accused Major Armstrong stated that all the officers appeared to be armed with pistols or revolvers. Armstrong was also unable to say if O'Hanrahan was armed but stated that his name did not appear on a list of those people found to have been unarmed.

Michael O'Hanrahan did not call any witnesses in his defence but made the following statement:

As a soldier of the Republican army acting under the orders of the Proivisional Goverment of that Republic duly constituted I acted under the orders of my superiors.

Court Martial Verdict

Michael O'Hanrahan was found guilty and sentenced to death by shooting. This sentence was confirmed by General Maxwell.

Between 4 and 4.30am on 4 May 1916, Michael O'Hanrahan was shot in the former stonebreakers yard at Kilmainham Prison. His remains were later buried in Arbour Lane Cemetery.