Max Karl Ernst Ludwig Planck was born on April 23, 1858, in Kiel.
When Planck was nine years old, his father received an appointment at the University of Munich, and Planck entered the city's renowned Maximilian Gymnasium. He started to study physics at the University of Munich in the fall of 1874, and received his doctoral degree in July 1878 at the unusually young age of 21. The following year he completed his Habilitationsschrift (qualifying dissertation) at Munich and became a Privatdozent (lecturer).
In 1885 he was appointed ausserordentlicher Professor (associate professor) at the University of Kiel. In 1889, Planck received an appointment to the University of Berlin, where he came to venerate Helmholtz as mentor and colleague. In 1892 he was promoted to ordentlicher Professor (full professor).
Max Planck made many contributions to theoretical physics, but his fame rests primarily on his role as originator of the quantum theory. Planck was 42 years old in 1900 when he made the famous discovery that in 1918 won him the Nobel Prize for Physics: The quantum of action, now known as Planck's constant h, relates the energy of radiation to its frequency. He also evaluated the Boltzmann constant, Avogadro's number, and the charge of the electron. Planck became permanent secretary of the mathematics and physics sections of the Prussian Academy of Sciences in 1912 and held that position until 1938; he was also president of the Kaiser Wilhelm Society (now the Max Planck Society) from 1930 to 1937.
In 1909, his first wife Marie Merck died, leaving Planck with two sons and twin daughters. The elder son, Karl, was killed in action in 1916. The following year, Margarete, one of his daughters, died in childbirth, and in 1919 the same fate befell Emma, his other daughter. The younger son, Erwin, was implicated in the attempt made on Hitler's life on July 20, 1944, and in early 1945 he was killed by the Gestapo. At war's end, Planck and his second wife, Marga von Hoesslin, moved to Göttingen. There, on October 4, 1947, in his 89th year, he died.