He began to article in law with his father, but served as a captain in the Quebec militia during the War of 1812 and took part in the Battle of Châteauguay in 1813.
In 1816, Panet was elected to the Legislative Assembly of Lower Canada for Northumberland and served until 1824, when he was unable to run due to poor health.
Panet resigned his seat in 1832 to accept an appointment as judge in the Court of King's Bench for Quebec district.
During the Lower Canada Rebellion, Panet earned the ire of the British authorities by declaring the suspension of habeas corpus by the Special Council in 1838 unconstitutional.
Panet and Elzéar Bédard were suspended from their duties as judge by colonial administrator Sir John Colborne.