During the 1995 Quebec referendum he headed the "No" campaign, in opposition to the PQ's proposals for Quebec sovereignty. He served as Liberal party leader and leader of the Opposition until 1998 when he was succeeded by Jean Charest.
Johnson, who worked for Lockheed Martin on upgrading Saudi AH-64A Apache attack helicopters, was kidnapped and taken hostage by a terrorist group claiming to be part of Al-Qaida.
Johnson made some statements similar to the ones made by Nick Berg before Berg was killed (not long before Johnson was taken hostage).
Johnson was described by his son, Paul Johnson III, as a lover of Saudi Arabian culture who often sent verses of the Koran to his daughter.