Roger was the son of Hugh de Montgomery and his wife Josceline. She was the niece of Gunnora, Duchess of Normandy. Roger held the lands of Saint-Germain-de-Montgommery and Sainte-Foy-de-Montgommery. Both had traces of early castles. He became the Viscount of the Heismois about the same time Robert I of Normandy became Duke in 1027. But as the viscount he witnessed a royal charter to the abbey of St. Wandrille . Like Duke Robert, Roger began taking properties that belonged to the church. These included () half the town of Bernay. He took over a woodland at 'Crispus Fagidus' which belonged to Jumièges Abbey. He put an end to a market held by the same abbey and took it into his own domain. Later he seemed to have a change of heart. He returned the market to the abbey and paid restitution for their losses.