Magdalene Sibylle was born in Dresden, the third surviving daughter and sixth surviving child of John George I, Elector of Saxony, and Magdalene Sibylle of Prussia.

She was engaged in 1633 and married on 5 October 1634 to Christian of Denmark-Norway, who had been elected Prince of Denmark (heir apparentin 1610.

Her husband died during a trip to Saxony, which she was accompanying him on, and the marriage ended childless.

In 1651 she was engaged to Duke Frederick Wilhelm II of Saxe-Altenburg, and on 11 October 1652, she married him in Dresden.

She had three children with her second husband:[citation needed] She visited Denmark in 1662 for the engagement of Princess Anne Sophie of Denmark to John George III, Elector of Saxony.