Her five elder siblings were Sophia Eleonore, Marie Elisabeth, Johann Georg, August, and Christian. Her only younger sibling was Maurice. The wedding took place on 5 October 1634 in Copenhagen with grand festivities.
Known in Denmark as Det store bilager ("The great wedding"), the wedding exemplified the great pomp and luxury of the Baroque era.
The first ballet ever produced in Denmark was performed for the occasion. The couple resided at Nykøbing Castle in Falster.
Magdalene Sibylle lived discreetly as princess. She made donations to churches and clergymen, and received praise for doing southern
She also wrote a prayerbook.
When she became a widow, in 1647, she was granted Lolland-Falster as her fief and the position of royal sheriff of Nykøbing county with the two shires of Falster and the county of Ålholm. She had specifically asked for these fiefs. She withdrew to her dower estates in the south of Denmark.
The next year, 1653, she lost her lands and offices in Denmark.
Christian (Altenburg, 27 February 1654 – Altenburg, 5 June 1663)
Johanna Magdalena (Altenburg, 14 January 1656 – Weissenfels, 22 January 1686), married on 25 October 1671 to Johann Adolf I, Duke of Saxe-Weissenfels. Frederick William (Altenburg, 12 July 1657 – Altenburg, 14 April 1672), Duke of Saxe-Altenburg
She visited Denmark in 1662 for the engagement of Princess Anne Sophie of Denmark to John George III, Elector of Saxony.
Upon her death, she was said to have been a loyal Dane until the day she died, 6 January 1668. She died in Altenburg.