He was appointed a general officer in 1794 for distinguishing himself during the War of the Pyrenees.

His division was in the first wave of the 1808 invasion of Spain, which precipitated the Peninsular War.

After being sent home from Spain, Merle was assigned to lead a division in the French invasion of Russia.

He embraced the Bourbon cause in 1814, retired from the army in 1816, and died at Marseilles in 1830.

Merle is one of the names inscribed under the Arc de Triomphe on Column 35.