Architect. Brother of Pierre, Charles, and Jean-Baptiste Le Roy.

Received the grand prize for architecture from the Academy (1751). Traveled throughout Italy and Greece. Admitted to the Academy of Architecture. Interested in navigation. Constructed a small vessel, the naupotame. Member of the Académie des inscriptions et belles lettres (1770), and of the American Philosophical Society.

Wrote Ruines des plus beaux monuments de la Grèce (1758, 1770), Histoire de la disposition … que les chrétiens donnerent à leurs temples (1764), Observations sur les édifices des anciens peuples (1767), and Marine des anciens peuples (1777).