In the religious wars from 1621 onwards his elder brother chiefly commanded on land and in the south, Soubise in the west and along the sea-coast.

His exploits in the conflict have been sympathetically related by his brother, one of the most highly regarded military critics of the time.

[1] The guidons he seized from Royalist forces when he took control of Les Sables-d'Olonne during the Huguenot rebellions were installed in the Hôtel de Ville in La Rochelle in 1622.

[2] Soubise's chief exploit was a singularly bold and well-conducted attack (in 1625) on the Royalist fleet in the river Blavet (which included the cutting of a boom in the face of superior numbers) and the occupation of the islands of Ré and Oléron in 1625, leading to the Siege of Saint-Martin-de-Ré in which Louis XIII recovered the island of Ré.

[1] When surrender became inevitable he fled to England, which he had previously visited in quest of succour.