Paisley becomes a Protestant evangelical minister in 1946 and remains one for the rest of his life. In 1951, he co-founds the fundamentalist Free Presbyterian Church of Ulster and is its leader until 2008. Paisley becomes known for his fiery speeches and regularly preaches and protests against Catholicism, ecumenism and homosexuality. He gains a large group of followers who are referred to as “Paisleyites.”
Paisley becomes involved in Ulster unionist/loyalist politics in the late 1950s. In the mid-late 1960s he leads and instigates loyalist opposition to the Catholic civil rights movement in Northern Ireland. This leads to the outbreak of The Troubles in the late 1960s, a conflict that engulfs Northern Ireland for the next thirty years. In 1970, he becomes Member of Parliament for North Antrim and the following year he founds the Democratic Unionist Party (DUP), which he leads for almost forty years. In 1979, he becomes a Member of the European Parliament.
Throughout the Troubles, Paisley is seen as a firebrand and the face of hard-line unionism. He opposes all attempts to resolve the conflict through power-sharing between unionists and Irish nationalists/republicans, and all attempts to involve the Republic of Ireland in Northern affairs. His efforts help bring down the Sunningdale Agreement of 1974. He also opposes the Anglo-Irish Agreement of 1985, with less success. His attempts to create a paramilitary movement culminate in Ulster Resistance. Paisley and his party also oppose the Northern Ireland peace process and Good Friday Agreement of 1998.
In 2005, Paisley’s DUP becomes the largest unionist party in Northern Ireland, displacing the Ulster Unionist Party (UUP), which has dominated unionist politics since 1905. In 2007, following the St. Andrews Agreement, the DUP finally agrees to share power with republican party Sinn Féin and consent to all-Ireland governance in certain matters. Paisley and Sinn Féin’s Martin McGuinness become First Minister and deputy First Minister respectively in May 2007. Paisley steps down as First Minister and DUP leader in May 2008 and leaves politics in 2011. Paisley is made a life peer in 2010 as Baron Bannside.
In November 2011, Paisley announces to his congregation that he is retiring as a minister. He delivers his final sermon to a packed attendance at the Martyrs’ Memorial Hall on December 18, 2011, and finally retires from his religious ministry on January 27, 2012.
Paisley dies in Belfast on September 12, 2014. He is buried in Ballygowan, County Down on September 15 following a private funeral and a public memorial for 800 invited guests is held in the Ulster Hall on October 19. A New York Times obituary reports that late in life Paisley had moderated and softened his stances against Roman Catholics but that “the legacies of fighting and religious hatreds remained.”