He joined the Troupes de la Marine in 1733 and became an assistant engineer in 1739.
Chaussegros took part in raids against the British in New England, helped maintain French fortifications in New France and was in charge of the construction of Fort Saint-Jean.
In 1753, he married Louise, the daughter of François Martel de Brouague, commandant of the Coast of Labrador.
He took part in Louis-Joseph de Montcalm's capture of Fort Oswego in 1756 and, in 1757, was promoted to captain for his success at the Battle of Fort Bull.
He was wounded at the Battle of the Plains of Abraham and sent back to France in 1761.
His campaign journals are held by a government library in Quebec, and are important historic resources.
In France he had become the seigneur of Léry after his father's death.

At some point, Chaussegros de Léry produced a finished copy of a map of the west.
The original work had been made by Christopher Dufrost de La Jemeraye, a nephew of Pierre Gaultier de Varennes et de La Vérendrye.

Chaussegros de Léry was not given any opportunities by the French.
He returned to Quebec in 1764 by way of England.
There he was named chief road commissioner by Governor Guy Carleton in 1768, and also served on the Legislative Council and Executive Council of Quebec.
In 1792, he was named to the Legislative Council of Lower Canada.
He sold the seigneury of Léry in 1766 but later he acquired the seigneuries of Perthuis, Rigaud-Vaudreuil, Gentilly, Le Gardeur and Sainte-Barbe.

He died at Quebec in 1797.
He joined the Troupes de la Marine in 1733 and became an assistant engineer in 1739. Chaussegros took part in raids against the British in New England, helped maintain French fortifications in New France and was in charge of the construction of Fort Saint-Jean. In 1753, he married Louise, the daughter of François Martel de Brouague, commandant of the Coast of Labrador. He took part in Louis-Joseph de Montcalm's capture of Fort Oswego in 1756 and, in 1757, was promoted to captain for his success at the Battle of Fort Bull. He was wounded at the Battle of the Plains of Abraham and sent back to France in 1761. His campaign journals are held by a government library in Quebec, and are important historic resources. In France he had become the seigneur of Léry after his father's death.
At some point, Chaussegros de Léry produced a finished copy of a map of the west. The original work had been made by Christopher Dufrost de La Jemeraye, a nephew of Pierre Gaultier de Varennes et de La Vérendrye.
Chaussegros de Léry was not given any opportunities by the French. He returned to Quebec in 1764 by way of England. There he was named chief road commissioner by Governor Guy Carleton in 1768, and also served on the Legislative Council and Executive Council of Quebec. In 1792, he was named to the Legislative Council of Lower Canada. He sold the seigneury of Léry in 1766 but later he acquired the seigneuries of Perthuis, Rigaud-Vaudreuil, Gentilly, Le Gardeur and Sainte-Barbe.
He died at Quebec in 1797.
Gaspard-Joseph Chaussegros de Léry (1721-1797)