After his release, he continued to serve on the IRA Army Council and lead all financial dealings for Sinn Féin. In the 1990s, the IRA and Sinn Féin began to work on seeking peace. Cahill served on the council that called a cessation on 21 July 1997. Cahill attended several of the talks that finally led to the Good Friday Agreement on 10 April 1998. Shortly after the agreement was made, Cahill resigned as treasurer of Sinn Féin. To honour his service, he was made honorary Sinn Féin Vice-President for life. Cahill served the republican movement in Ireland all his life, as one of the longest-serving political activists in Ireland of any political party.