He completed legal studies at the Jagiellonian University under the supervision of the eminent Conservative thinker Władysław Leopold Jaworski, and then took up work at the Department of Law of Stephen Báthory University of Vilnius, becoming assistant professor. Mycielski was involved in secret teaching during the Second World War. After the war, in December 1945, he undertook to create the Department of State Law at the University of Wrocław, which he then headed until 1971, except for the years 1953-1956, when he was expelled from the university as an ‘opponent of the new regime’. He was politically ‘rehabilitated’ in the wake of the so-called Gomułka’s Thaw of October 1956, the short-lived moderation of Poland’s Communist authorities’ political line following Władysław Gomułka’s rise to power. In 1959-1960 Mycielski held the post of dean of the Department of Law of the University of Wrocław. In 1993, he received the title of Doctor Honoris Causa of that institution. His major works include Polskie prawo polityczne (1947), and Zarys nauki prawa państwowego (pt. 1, 1960).