Russell joined the Irish Volunteers in 1913. He participated in the 1916 Easter Rising as an officer in Dublin Brigade's 2nd Battalion, under Thomas MacDonagh. Following the Rising he was interned in Frongoch and Knutsford. After the Irish War of Independence began, he was attached to the IRA General Headquarters Staff (GHQ) and became IRA Director of Munitions in 1920. During the Irish Civil War, he fought against the Anglo-Irish Treaty with the Anti-Treaty IRA. In 1925, after the civil war, he was jailed in Mountjoy Prison but escaped on 25 November in a breakout he helped organise.