The Grodno Sejm, held in the fall of 1793, nominated him for a membership in a military commission; this caused him to be viewed with suspicion by the majority of the dissatisfied military, and he was not included in the preparations for the upcoming uprising. Thus he was taken by surprise when the Kościuszko Insurrection erupted, and his own brigade mutinied. He declared his support for the insurgents after the liberation of Warsaw, and from then on took an active part in the uprising, defending Warsaw and leading an army corps in support of an uprising in Greater Poland. His courage was commended by Tadeusz Kościuszko himself, the Supreme Commander of the National Armed Forces, who promoted him to the rank of general.