After Sinn Féin's sweeping victory in the November 1918 general election and the setting up of the First Dáil in 1919, it was clear that the British government and the Republicans were on a collision course. The War of Independence began with the Soloheadbeg ambush on the same day that the first Dáil met.
Tomás MacCurtain took an active role in the War of Independence. Originally from Ballyknockane in County Cork, he became involved with the Gaelic League, the Irish Republican Brotherhood and the Irish Volunteers. He was in command of the Irish Volunteers in Cork during the 1916 Rising in Dublin. Although no violence took place in Cork during the Rising, MacCurtain was subsequently arrested and imprisoned.
Following Sinn Féin's victory in the local elections of January 1920, Tomás MacCurtain was elected Lord Mayor of Cork on 31 January 1920, the first Republican to hold the office. His term as Lord Mayor was brutally cut short. In the early hours of the morning of 20 March 1920, members of the Royal Irish Constabulary burst into his house and shot him dead. After the killing they ransacked the house. The shocking murder outraged public opinion and brought near universal condemnation. Cork went into mourning for its murdered first citizen. A massive crowd attended his funeral. At the coroner's inquest into the killing the jury passed a verdict of willful murder against Lloyd George and certain inspectors of the R.I.C. One of the named inspectors, Oswald Swanzy, was shot dead in Lisburn on 22 August 1920.