He was the son of John William Friso of the Frisian branch of the house of Orange-Nassau and a descendant of the brother of William the Silent. After the death of his father, he became at age seven chief executive and military commander of the province of Friesland.
In an effort to quell internal strife amongst the various factions, in 1747 the States-General selected William IV as their leader, making it a hereditary position. At first, he was popular with the people when he spoke out against the power and wealth of the Dutch business establishment. Nevertheless, he was Director-General of the Dutch East India Company and his alliance with the business class deepened while the disparity between rich and poor grew. He served as stadtholder of all the Netherlands until his death in 1751.