The son of Gaspar Schetz and Catharina d'Ursel from the noble Ursel family, he was baptised in Antwerp in August 1564. His parents had 21 children in total, of which 8 survived to adulthood. His father was from the Schetzenbergh family, a German patrician family from Schmalkalden, and he was the chief banker in Antwerp, financing several merchants such as his brothers Melchior and Balthazar, who traded to Russia and Brazil. Gaspar was also banker to Philip II of Spain, giving him a political role and making him a leading figure in the Antwerp of the second half of the 16th century.