Eddie McAteer was first elected as an Nationalist Party MP in 1945. He would hold various seats in the Derry region until he lost his Foyle seat to John Hume of the SDLP in 1969.
The Nationalist Party did not become one political party until 1966. Before that, candidates stood under a Nationalist Party umbrella. Prior to Eddie McAteer, Joe Devlin was its most successful politician. In 1965, the Nationalist Party agreed to become the official opposition party in the House of Commons and thereafter became heavily involved in the Civil Rights movement.