Maciej Kalenkiewicz was born July 1, 1906, in a small manor in Pacewicze, to Jan Kalenkiewicz, an impoverished member of the Polish gentry and a peasant politician, and Helena née Zawadzka. He graduated from a gymnasium in Vilna (modern Vilnius) and then the Cadet Corps in Modlin. In 1924 he was admitted to the Officer Engineering School in Warsaw, where he took part in the May Coup d'État on the side of the government. In 1927 he graduated as an engineer, with the best marks at his year. After a yearly practice in the prestigious Modlin-based 1st Engineering Regiment, he applied for the faculty of Land Engineering of the Warsaw University of Technology. In 1934 he married Irena née Erdman and graduated as a qualified engineer.