During the Brabant Revolution, Vonck initially cooperated with Hendrik van der Noot and his faction of the Statists.

Vonck aimed to reform the existing structures rather than an Assemblée nationale as established by the French Revolution.

Vonck wanted to extend the representation of the three social classes in the States General: clergy, nobility and the bourgeoisie.

There he translated his earlier Considérations into Dutch with the title Onzeydige Aenmerkingen over den tegenwoordige ghesteltenis van Brabant ("Impartial testament on the present situation of Brabant") and he added to it a Kort historisch verhael tot inleyding uytgegeven door den advocaat Vonck ("Short historical introductory story issued by the lawyer Vonck").

He bequeathed to the poor of the municipality among others and gave orders for a scholarship to be founded which still exists and which is managed by the provincial administration of East Flanders.

His supporter and close friend Jan Baptist Chrysostomus Verlooy (1747–97), also a Brussels lawyer, wrote an essay, D'onacht der moederlycke tael ("On the neglect of the native language"), in 1788 which has been described a precursor to the Flemish Movement.