Though he was not one of the most high-profile members of the House of Commons, Jean-Charles Chapais worked to reform agricultural legislation, including the abolition of seigneurial tenure and the development of laws related to farming and settlement. He participated in the Québec Conference as the commissioner of public works.
In 1833, Chapais settled in Saint-Denis, near Kamouraska. It was there that he became known, first as a farmer, and later as a merchant and businessman. In fact, from 1833 to 1850, Chapais was responsible for all the measures that made Saint-Denis one of the province's best-organized municipalities.
Chapais agreed, with some reservations, to run in the election of 1851. He represented the riding of Kamouraska until Confederation in 1867, and the Champlain (Quebec) riding until 1873. Politically, Chapais tended to be conservative. Accordingly, he supported Augustin-Norbert Morin, Étienne-Paschal Taché and George-Étienne Cartier.
Appointed minister of agriculture in John A. Macdonald's first Cabinet, Chapais held the position until 1869, when he became receiver general. Macdonald pushed Chapais from Cabinet in 1873 as part of an attempt to make his party over.
Jean-Charles Chapais was named to the Senate in 1867 and occupied his seat until his death, in 1885.
Désilet, Andrée. "Chapais, Jean-Charles." Dictionnaire biographique du Canada. Vol. XI. Québec : Presses de l'Université Laval, 1983. P. 193-194