In 1806, when during the War of the Fourth Coalition, French armies approached the Vistula river, Dwernicki, together with his friend Augustyn Trzecieski, decided to find the so-called Patriotic Society, which planned an anti-Russian uprising.
In 1809, Dwernicki armed 80 men, crossed the Zbruch river, and joined Polish troops under Piotr Strzyżewski (May 27, 1809, near Tarnopol).
In 1810, Duke Józef Poniatowski awarded him the Virtuti Militari, and nominated him commander of a squadron in the 15th Uhlan Regiment, formed in Podolia.
His military skills were greatly appreciated by Russian Governor of Poland, Grand Duke Constantine Pavlovich, who awarded him several orders.
Following the battle, Dwernicki and his unit marched to Góra Kalwaria, and then engaged the Russians in several places, such as Warka, Kozienice, Puławy, Lublin and Zamość.
In early April 1831, Dwernicki crossed the Bug river, and marched into Volhynia, hoping to start the uprising in this province of former Polish–Lithuanian Commonwealth.
Dwernicki was a founder and member of several organizations, and was a very popular activist, whose house was visited by such people, as Louis-Napoleon Bonaparte and Gilbert du Motier, Marquis de Lafayette.
He became a friend of Count Adam Zamoyski, who supported him financially, and invited Dwernicki to visit his real estate in Lopatyn near Brody.