He was the strongest chess player in New Orleans in the first half of the 1840s.
In 1845, Rousseau played a match against the Englishman Charles Stanley for the title of chess champion of the US, the first contest ever for that title.
Rousseau lost the match (+8 −15 =8) and Stanley became the first US Champion.
In 1850, Johann Löwenthal paid a visit to New Orleans, and beat Rousseau five games straight.
Rousseau beat Winawer with the black pieces in Paris in 1867: