He was the son of the 1st Marquis de Ruvigny, a distinguished French diplomat, and a nephew of Rachel, the wife of Thomas Wriothesley, 4th Earl of Southampton.

Probably on account of his English connections he was selected in 1678 by Louis XIV to carry out the secret negotiations for a compact with Charles II, a difficult mission which he executed with great skill.

In 1694, with the rank of lieutenant-general, he was sent to command a force in English pay that was to assist the Duke of Savoy against the French, and at the same time to relieve the distressed Vaudois.

[citation needed] After some years spent in retirement, he was appointed in 1704 to command the allied forces in Portugal together with François Nicolas Fagel, a post which he sustained with honour and success until the Battle of Almanza in 1707, in which Galway, in spite of care and skill on his own part, was decisively defeated by the Duke of Berwick.

As most of his property in Ireland had been restored to its former owners, and all his French estates had long before been forfeited, Parliament voted him pensions amounting to 1500 pounds a year.