Sophie became Queen of Denmark when she was married to Frederik II in 1572. She was the daughter of Duke Ulrich of Mecklenburg and the mother of Christian IV.

Sophie was only 14 years old when she was married to Frederik II, who was 23 years older than her. Nevertheless, they had a harmonious marriage. She had no political power while Frederik II was alive but after his death in 1588, she played a more prominent role, for example as Guardian of the young Christian IV in Schleswig and Holstein. As such, she came into conflict with the government, which expelled her to the palace of Nykøbing Slot on the island of Falster.

Sophie proved to be an able administrator of her estates on Lolland and Falster. She was also engaged in large-scale trade and money lending, and several European princes borrowed money from her. They included her son, Christian IV, who had to borrow from her because of his costly wars.