He was born in Kapustynie in Volhynia and was educated at the school of the Basilians at Szarogrod, from which in 1785 he ran away in order to enlist as a volunteer in the Polish army. Chlopicki entered the army in 1785 and fought under Kościuszko in the Uprising of 1794. Warsaw was surrendered to the Russians on 8 November 1794, after which Chlopicki went to France and joined the Army of the Cisalpine Republic under General Jan Henryk Dąbrowski. In France he is known as Grégoire Joseph Clopicki de Necznia.