Maria was born into a wealthy noble family in Kiernozia, to Count Mathieu (Mateusz) Łączyński, a landowner and starosta of Gostyń; and Eva Zaborowska, whose family was wealthy. Maria had six siblings: Benedykt Jozef, Hieronim, Teodor, Honorata, Katarzyna and Urszula-Teresa. She grew up in her ancestral home, Kiernozia, where she also received her education. Nicholas Chopin, Frédéric Chopin's father, was one of her tutors. In 1794 Mathieu participated (and was mortally wounded) in the Battle of Maciejowice, a year before the final partition of Poland, when the Łączyński lands were incorporated into Russia, leaving behind a widow, seven children (five of them surviving into adulthood), and a dwindling livelihood.