He played a prominent military role in the Lower Canada Rebellion as Colonel of the cavalry at the Battle of Saint-Charles, afterwards seizing the Column of Liberty and carrying it in triumph back to Montreal.

As a Huguenot, and the son of a Royalist Colonel of the Swiss Guard who served with the British Army too, he was admitted to the elitist school of the Reverend John Strachan in Cornwall, Upper Canada.

Given the rank of colonel he led the cavalry at the Battle of Saint-Charles, and it is suggested that he personally seized the Column of Liberty before carrying it in triumph to Montreal with two subalterns.

Following the Rebellion, Gugy held the position of Police Magistrate at Montreal, and then from 1841 to 1846, he was appointed Adjutant-General to the Militia of Lower Canada.

As Adjutant-General, the party of Sir Louis-Hippolyte La Fontaine frequently targeted him for not placing enough French Canadians in the higher ranks of the militia.

After the Union of 1841, Gugy failed to win the parliamentary seat for Saint-Maurice when the supporters of his opponent, Joseph-Édouard Turcotte, seized the polling booth.

Gugy reacted with his customary spirit on the night of the burning, seizing several of the agitators to stop them from setting upon the Speaker, Augustin-Norbert Morin.

In 1853, he received another civil post as Inspector and Superintendent of Police at Montreal, but resigned the same year to retire to the estate at Beauport that he had inherited in 1840 from his father, together with the Seigneuries of Yamachiche, Rivière-du-Loup, Grandpré, Grosbois, and Dumontier.

The Dictionary of Canadian Biography said of his character: Hot-headed, irascible, endowed with a colourful nature, the bulky, loud-voiced colonel was not vindictive, or intolerant, or sectarian.

Towards, the end of his life Gugy often returned to Quebec, riding erect on horseback despite his 78 years, to ensconce himself in the library of the Palais de Justice and regale the young of all ages with the details of his former litigations and addresses to the court.