He founded the Maetschappy van Vlaemsche Letteroefening De Tael is gantsch het Volk, and he participated in several Flemish actions, such as the Vlaams petitionnement (1840), the Kunst- en Letterblad (1840), the Dutch Linguistic and Literary Conferences(vanaf 1849), the Rapport van de Grievencommissie (1856–1859) en the Vlaemsch Verbond (1861).
In 1847, he succeeded his friend Jan Frans Willems as member of the Royal Belgian Academy in Brussels, where he represented the Flemish cause, and he was one of the co-founders of the Willemsfonds.
In the first half of the 1850s Snellaert tried to win a seat on the city council with the support of the moderate Société l'Union and the progressives of the newspaper Broedermin.
However, due to the electoral victory of Judocus Delehaye he chose to join the Liberale Associatie ('Liberal Association'), where he was for a brief period a key figure of the pro-Flemish group.
His followers, including Jacob Heremans and especially Julius Vuylsteke turned away from him when it became clear that Snellaert, disappointed by the attitude of the Liberale Associatie, started to think again of establishing an ideologically neutral Flemish party.