[5] Willmann was born in Königsberg (Królewiec; today Kaliningrad), Duchy of Prussia a fief of Kingdom of Poland.

Michael went to the Dutch Republic in 1650 to learn from the masters, and he was inspired by the works of Rembrandt, Peter Paul Rubens, and Anthony van Dyck.

[6] After two years in the Netherlands, mostly spent in Amsterdam, in 1653 Willmann returned to Königsberg, passed his master's examination, and began to travel.

[7][8] Willmann's first known painting, Landscape with John the Baptist, commissioned by Abbot Arnold Freiberger of the Abbatia Lubensis abbey in Leubus (Lubiąż), Lower Silesia, dates from 1656.

[5] In May 1663 he converted from Calvinism to Roman Catholicism and took the baptismal names Leopold (after the emperor) and Lukas (after the patron saint of painters).

[5] Willmann's prosperity allowed him in 1687 to acquire a manor near Leubus and sponsor the educations of his son and stepson in Italy.

[5] Willmann was detailed in Academia, the 1683 Latin edition of Joachim von Sandrart's Teutsche Academie der edlen Bau-, Bild und Malereikünste.

[5] Painters influenced by Willmann include Wenzel Lorenz Reiner,[15] Petr Brandl, Johann Michael Rottmayr, and Franz Anton Maulbertsch.