Maurice was born in Kassel as the son of William IV, Landgrave of Hesse-Kassel, and of his wife Sabine of Württemberg.

Maurice's conversion was controversial since the Peace of Augsburg had only settled religious matters betweens Roman Catholics and Lutherans and had not considered Calvinists.

English strolling players ('Die Englische Comoedianten') were frequent visitors to, and performers in, towns and cities in Germany and other European countries, including Kassel, during the 16th and 17th centuries.

Landgraf Moritz (to use his German nomenclature) was a great supporter of the performing arts and even built the first permanent theatre in Germany, named the Ottoneum, in 1605.

In 1609, Maurice played a leading role in mediating the Treaty of Dortmund, which aimed to determine the succession of Julich-Cleves-Berg.