Franco-Flemish composer. Worked in and around Antwerp from 1545 as singer and choirmaster, becoming in 1559 maîre de chapelle at Saint-Gommaire of Lierre. He entered holy orders, but no date for his ordination is established. In 1562, he became music director of the Confrérie de Notre-Dame at Antwerp Cathedral, and was maître de chant there in 1563; on May 2, 1571 he was appointed maestro di capilla to the Flemish chapel of Philip II of Spain. until his death. As a musician of the Court, he composed in 1564 a Te Deum for the entry of Margaret of Parma into Antwerp. He published a volume of 3-part chansons and motets in 1569; a Mass and some 2- and 3-part chansons appeared in anthologies.
Another musician, Jan-Jacob van Turnhout (or Jean-Jacques de Turnhout (c 1545-after 1618), maître de chapelle at Bruxelles from 1594 to 1618, may have been related to Gérard (as a very young brother, or son).