After World War II he followed his father's footsteps, who had died in the Nazi concentration camp of Bergen-Belsen. From 1949 up to 1958 he was province council member in Antwerp. In 1961, he became a member of parliament and in 1965, he changed to the senate where he remained until his death. Vanderpoorten led several ministries during his political career. For the PVV-PLP, he was minister of internal affairs in the government Paul Vanden Boeynants-Willy De Clercq (1966–1968), minister of justice in the government Edmond Leburton (1973–1974), in the government Leo Tindemans-II (1974–1977) and in the government Wilfried Martens-III (1980) and in addition vice-prime minister and minister for institutional reforms in that same government. In 1979, he took part in the first direct European elections and was member of the European Parliament in Strasbourg up to 1980. In 1983, he was appointed by the king as Minister of State. He was burgomaster of Lier (1982–1984). He was president of the Liberaal Vlaams Verbond (1957–1966, 1969–1973).
