He was born Kaj Harald Leininger Petersen at Lolland, Denmark. He was raised by a family called Munk after the death of his parents.
After a brief period of Nazi admiration around 1935 he turned a strong opponent. His plays Han sidder ved Smeltediglen ("He sits by the smelting pot") and Niels Ebbesen were direct attacks on Nazism. He was assassinated by Nazi sympathisers.
His plays, many of which have been performed at the Royal Theatre, Copenhagen, and elsewhere, include:
Pilatus (1917. Published 1937), Ordet (1925), En Idealist (1928), I Brændingen (1929), Cant (1931), De Udvalgte (1933), Sejren (1936), Han sidder ved Smeltediglen (1938), Egelykke (1940), Niels Ebbesen (1942), Før Cannae (1943).
Visit http://www.kajmunk.dk for further information