He oversaw the government-in-exile based in London under Queen Wilhelmina during the German occupation of the Netherlands.

Pieter Sjoerds Gerbrandy was born on 13 April 1885 in the village of Goënga, near Sneek, in the province of Friesland.

The German victory at the Battle of the Netherlands in 1940 made the Dutch royal family and many leading politicians flee to London and form a government-in-exile.

With Dirk Jan de Geer's resignation the same year, Queen Wilhelmina appointed Gerbrandy as prime minister of the Dutch government-in-exile.

In 1950, Gerbrandy published Indonesia, which offered an explanation of the history of the relationship between the Netherlands and the Dutch East Indies (now Indonesia) from the 1600s to 1948, which included "The Indies under Dutch rule", "The Rule of Law", "The Japanese Occupation", and "Chaos", with each section outlining Gerbrandy's observations.