The Unionists objected due to the fact that the Agreement was imposed on the people with no referendum, and to the notion of a foreign government.

Paisley is a former member of the Orange Institution. In 1995, he played a part in the first standoff over marching at Drum Cree between the Orange Order and local residents of the Garvaghy Road.

The march passed off after the decision was made by the RUC to allow it, and Paisley ended the march hand in hand with David Trimble who appeared to perform a "Victory Jig" which was seen by some as an act.

During fresh elections in 2003 Paisley and the DUP campaigned on the need for re-negotiation of the Belfast Agreement and emerged from the elections as the leading party entitled to the position of First Minister with Sinn Féin entitled to the Deputy First minister position. Progress could now only be achieved with Paisley's agreement. He refused to accept Sinn Féin in Government without further progress, and the British Government maintained the suspensions of the institutions.

Paisley and the DUP entered negotiations with the Governments and the other parties on the steps required and the changes needed to the Belfast Agreement. The December 2004 Comprehensive Agreement upheld the principles of the Belfast Agreement but fell apart on the DUP's demand for photographic evidence of IRA decommissioning. Following IRA disarmament in September 2005, the Governments set deadlines for the DUP and Sinn Féin to agree on a new Executive, with the alternative being direct rule from London.

In the October 2006 St. Andrews Agreement, Paisley and the DUP agreed to new elections, and support for a new executive including Sinn Féin, subject to Sinn Féin acceptance of the Police Service of Northern Ireland. This reversed decades of Paisley opposition to Sinn Féin Sinn Féin did endorse the PSNI, and in the subsequent election Paisley and the DUP received an increased share of the vote and increased their assembly seats from 30 to 36.

On the 26th March 2007, the date of the British Government deadline for devolution, Paisley led a DUP delegation to a meeting with a Sinn Féin delegation led by Gerry Adams, which agreed on a DUP proposal that the executive would be established on May 8th.

Later in April, Paisley met with Taoiseach Bertie Ahern and publicly shook his hand, something he had refused to do until there was peace in Northern Ireland.

On May 8th power was devolved, the Assembly met, and Paisley was elected as First Minister of Northern Ireland with Sinn Féin's Martin McGuiness as the Deputy First Minister.

On March 4, 2008 Ian Paisley announced that he will step down as the First Minister and leader of the DUP in May 2008.