He worked together with Jean Dumont de Carelskroon, jurist of Charles VI, Holy Roman Emperor, and author of the Corps Universel Diplomatique du Droit des Gens, to which he published an addition in 1739. Rousset's Recueil historique and Intérêts presens were the international reference works for contemporary diplomats. Rousset emphasized the importance of voluntary, or secondary international law: by contracting treaties, monarchs, republics and cities constantly amended, altered or created international law. As natural law was concerned, Rousset referred to the 17th Century theorists Hugo Grotius and Samuel Pufendorf. For Rousset, his task in assembling formal acts was to give insight to the rulers and their advisers. As he stated in the foreword to his 1733 Intérêts presens: Doing so, Rousset believed disputes between sovereigns could be settled by established procedures, following both older and newer treaties. War could thus be avoided by taking the road of informal and alternative dispute settlement mechanisms. In this, Rousset followed the established policy of French Prime MinisterAndré-Hercule de Fleury and British Prime Minister Robert Walpole, who already continued the views of the French Regent, Philippe II, Duke of Orléans, his minister Guillaume Dubois and the British minister James Stanhope, 1st Earl Stanhope. Next to the publication of treaties, Rousset also was an authority concerning ceremonial, a sensitive issue between sovereign courts. Rousset's texts were quoted or even copied extensively in French archival sources.
Rousset, son of an exiled Huguenot and a former combatant at the Battle of Malplaquet, is also known for his activities as a journalist, some of his correspondence has been published. In 1748 he became involved in the Orangist revolution in the Netherlands. He was suspected of publishing anonymous pamphlets against the Stadtholderless regime and of leaking diplomatic information, which landed him in prison for a while. He was freed on the order of the newly appointed stadtholderWilliam IV, Prince of Orange, who appointed him his personal historian and councillor. The stadtholder and he fell out, however, after Rousset joined the leadership of the democratic Doellisten faction in Amsterdam, and Rousset was fired as personal historian of the stadtholder. After he published a pamphlet that earned a complaint from the French ambassador he was forced to flee to Brussels. After having spent a few years there, apparently in the service of the government of the Austrian Netherlands, he returned to the Dutch Republic in 1752, where he retired to the village of Maarssen till his death on 13 August 1762.