Working in a style, which combined his Flemish roots with the profound influence of Italian art, he was known for his portraits and altarpieces.
He joined the Bentvueghels, the informal association of mainly Dutch and Flemish painters resident in Rome.
[5] The admission criteria of the Accademia were very strict and considered both the artistic merit and personal qualities of the candidate.
[8] The seventeenth-century Italian biographer Giovanni Battista Passeri wrote that Cousin's passion for women induced him to neglect his work and squander all his money.
He traveled to Loreto, where he made a painting for the high altar of the church of Santa Margherita, and then to Pesaro, where he worked in the cathedral.
[5] He continued to paint portraits and historical themes, and also made designs (cartons) for tapestries that were then manufactured by local weavers.
For the Spanish king he made a few cartons for tapestries and a large painting entitled Venus Lamenting the Death of Adonis (around 1656-1557).
[5] Louis Cousin painted mythological subjects and religious works[5] and was also very appreciated as a portrait painter.
Jan van Kessel the Elder, an artist specialised in still lifes with flowers, insects and animals, executed the decorative borders that frame the various episodes.