With his mistress Karin Hansdotter (1532–1596) he had at least four illegitimate children. John cared for Karin and their children even after he married Catherine Jagiellon, in 1562. He found Karin a husband who would care for her and the children. In 1561, she married nobleman Klas Andersson (Westgöthe), a friend and servant of John. They had a daughter named Brita.
With his mistress Karin Hansdotter (1532–1596) he had at least four illegitimate children John cared for Karin and their children even after he married Catherine Jagiellon in 1562 He found Karin a husband who would care for her and the children In 1561 she married nobleman Klas Andersson (Westgöthe) a friend and servant of John They had a daughter named Brita