She was most likely named after her grandmother Johannetta of Isenburg-Neumagen (1500–1563), daughter of Salentin VII, lord of Isenburg and Neumagen (1462–1533).
After his marriage he and his family settled in a Castle in the country near the city of Berleburg.
Her mother gave birth to two more children, Juliana in 1562 and George II in 1565, before she died in 1565.
[2] They grew up at the ancestral Wittgenstein Castle on a hilltop overlooking Bad Laasphe to a former hunting lodge near Berleburg.
In 1586 at the 14th of June at Dillenburg Castle at the age of 25 she married Count John VI, the eldest son of William the Rich and Juliana of Stolberg, who was 50 years old by then.