French commission seeker.
Entered French artillery corps (1769); lieutenant (1772). Transferred to the navy after his regiment was dissolved (c. 1775); studied mathematics and drawing. Subsequently returned to the army, served in India, and rose to the rank of general (1795).
Son of Baltazar and Thérèse (Royer) Roman of Grenoble. Brother of Charles-Noël-François Romand d’Isle (1743-1784), an artillery officer in the Continental Army.