In 1779, Grimouard commanded the frigate Minerve. He captured the British ship Debora, and took part in the Battle of Grenada on 6 July 1779.[2] That same year, he was made a Knight in the Order of Saint Louis.[2]
Grimouard was promoted to counter admiral in July 1792, and was appointed commander of the naval forces in Brest. In January 1793, he was promoted to vice admiral.[2]