Moritz war das fünfte Kind des Kurfürsten Friedrich V. von der Pfalz und König von Böhmen und seiner Gattin Elisabeth Stuart. "Her [Elisabeth Stuart's] fifth experience of labour lasted little over an hour. Her choice of a name for her infant showed Europe that she had recovered her spirits [nach der Flucht aus Böhmen]. The dark child [dunkle Haare und braune Augen] born at Cüstrin on January 6th, 1621, was christened four days later after his martial great-uncle, the Prince of Orange - 'Maurice, because he will have to be a fighter.'" (in: Carola Oman: Elizabeth of Bohemia, id., p. 236).
"At fifteen he had grown to an absurd height, overtopping Charles Louis [seinen Bruder]. At seventeen, having assisted the Prince of Orange to capture Breda, he had expected to be allowed a command in the army for the invasion of the Palatinate. Elizabeth had declared in the hour of his birth that this child must prove a soldier, but she thought now that he must first learn to resemble a Christian gentleman. Although the Voorhout was a fashionable neighbourhood, it was badly lit at night, and cup-shotten gallants delighted in breaking the windows and unscrewing the door-knockers of its sumptuous mansions. Complaints that Prince Maurice, in rowdy company, had been scaring respectable citizens and their wives, after nightfall, in the streets of the Hague, reached his mother. He took part in a duel, which ended fatally for one assailant." (in: Carola Oman: Elizabeth of Bohemia, id., pp. 348-349).
Er nahm an den englischen Bürgerkriegen teil und starb bereits mit 31 Jahren bei einem Schiffbruch auf hoher See bei den Britischen Jungferninseln in der Karibik.