Sean (Jack) O'Leary was a Bank Clerk in the Munster Bank who arrived at Nenagh in 1919 having transferred from Clare. Originally from Ballydribeen in Killarney, he was the eldest of six children born to Jerome O'Leary and Joanna Cronin. He was a quite an unassuming young man and held in high regard by both his colleagues at the bank and his fellow comrades on the Hurling and Gaelic football field. He was a member of the North Tipperary Gaels. He was also a member of a local Nenagh A.S.U. of 1st Brigade led by Ned O'Leary. 

The British army had wished to speak with Sean for some time. IRA records show that he was a member of the 1st Brigade Active Service Unit. Upon his arrival he was involved in the destruction of a Military vehicle and the commandeering of a Black Maria. In October 1920, his 'digs' were raided by armed and masked Policemen. Similar actions led to the death of Dinny Carey on 06/11/1920 so it was a very creditable threat. Because of this and their intent to murder him, Sean went 'on the run'.  This meant he could share his expertise so we find him at the ambush at Kilcommon. He had also taken part in an attempted ambush in Dromineer. The previous day on the 27th of March, or Easter Saturday, Sean had been part of an armed unit that rescued Volunteer Paddy McCarthy of Kilmallock, from armed guards at Nenagh District Hospital. They took Paddy to a safe house near Moneygall. Sean spent that night in a dugout. The following day, Easter Sunday he met and dined with Paddy McCarthy, Tom Waters, Eddie Ryan and Joe Starr (twin brother to Pat) at Joe Mangan's. They set out for the Silvermines to visit a sick comrade. All the men were unarmed.

An Auxiliary patrol of two cars were returning from Dublin to their billet at G Coy headquarters at the Lakeside Hotel in Ballina. Another version in the Nenagh News 02/04/1921 states it was a purpose led search and seek mission out of Nenagh comprising Military and R.I.C. In any case they spotted Sean with 4 others in a field outside of Moneygall. Sean had come to Moneygall to see a Dentist as he was suffering with Toothache. Otherwise they were travelling the wrong way if they wished to go towards Silvermines. The unarmed men dispersed on seeing the patrol stopped. Failing to respond to calls to halt and on seeing them taking flight, the Auxillaries opened fire on the fleeing men. 

Mangan and Starr, jumped a wall and escaped. There was little cover for the others so they scattered as best they could but were captured. Paddy McCarthy was re-arrested as was Eddie Ryan.

Sean was shot twice, once in the right knee and also in the left thigh.  His A.S.U. colleague Tom Waters was badly wounded in the thigh later resulting in a permanent disability (amputation). Waters was actually on the run from activity in Belfast. Although Sean was brought to Nenagh Hospital by the British.  There had been some talk of removing him to the Military wing of the Barracks in Summerhill, Nenagh but the sisters in the Infirmary refused to allow it until both men had been seen by a Medical Officer. Sean later died of his wounds between midday and 13.00 hours on 28/03/1921. A large crowd gathered at his bedside and the rosary was recited in both Irish and English. His remains were repatriated by motorised hearse to Limerick Junction and from there by train to his home in Killarney. He was buried in the family plot at Muckross Abbey. 

At the Court of Inquiry assembled at Nenagh on 04/04/1921, South African born Temporary Cadet Lieutenant Gordon Temple - Bodley claimed to have opened fire resulting in the wounding of two of the running men, O'Leary and a Bantry Electrician employed by Nenagh U.D.C., Thomas Waters. The driver, Geoffrey Bateman - Hope corroborated this version. Hope stated First Aid was administered to Sean at the site. Bodley confirmed this also. Dr A.D. Courtenay stated that Sean died as a result of Shock, Haemorrhage and loss of blood.

Hope would later be awarded an O.B.E. in 1944. Bodley would later appear at Bow St, London charged with Theft and Receiving on 24/10/1923. Sean is remembered on the monument to the Fallen in Banba Square in Nenagh.

Banba Square Monument