On 20 November 1671 at Friedenstein Castle in Gotha, she married Bernhard I, who at the time ruled Saxe-Gotha jointly with his brothers, and later became the first Duke of Saxe-Meiningen.

Bernhard built a castle here, which he named Marienburg, after Marie Hadwig.

The coat of arms of Henneberg showed a black hen.

Shortly before the scheduled move from their residence in Ichtershausen to Meiningen, Marie Hedwig stated that she would never enter the land of the black hen.

She was only 32 years old, and died 9 weeks before the scheduled move to Meiningen.