During World War II De Quay was co-founder of the controversial Dutch Union in July 1940 but the organisation was disbanded by the German occupation authority in December 1941.

De Quay continued to be active in politics and in September 1946 was nominated as the next Queen's Commissioner of North Brabant taking office on 1 November 1946.

De Quay withdrew from public life and lived in retirement until his death in July 1985 at the age of 83.

He holds the distinction as the leading the first cabinet to have completed a full term after World War II and his premiership is consistently regarded both by scholars and the public to have been average.

The following year he was awarded a doctorate for his thesis on the contribution of sensory and motor factors to the learning and labour process.

In July 1940 he formed the Triumvirate of the controversial nationalist Dutch Union with Louis Einthoven and Hans Linthorst Homan.

In August 1940 De Quay started secret meetings with the fascistic Nationaal Front in order to fuse the two organisations.

Following the liberation of the area south of the rivers in late 1944, he became chairman of the Board of Commissioners for Agriculture, Industry, Trade and Commerce set up to restore the national economy.

Shortly after the installation of the new government, minister of defence Ven den Bergh resigned for personal reasons (family affairs with his United States wife and children).

In 1961 minister Van Rooy of social affairs resigned after criticism of how he dealt with the new child benefit law.