He became an architect in 1900 having studied at the École des Beaux-Arts. In 1902 he became a monk of the Benedictines of Solesmes. These monks were in exile in England, and Bellot began building Quarr Abbey on the Isle of Wight.
In the Netherlands Bellot designed St. Paul's Abbey, Oosterhout, for the Order. He designed several churches in the Netherlands, France, Belgium, Canada and Portugal. Most of these are built largely of concrete or brick which were his preferred materials.
Bellot was a member of L'Arche, an organisation whose goal it was to use modern materials and art for religious purposes. In Canada, where he moved in 1937, he influenced several architects (i.e. Dom Claude-Marie Côté, also a Benedictine monk, and Adrien Dufresne, a layperson) and his architectural influence became known as "Bellotism".
His ideas are expounded in Propos d'un bâtisseur du Bon Dieu which was published posthumously in 1949; it is based on lectures he gave in Canada in 1934.
- St. Paul's Abbey, Oosterhout, the Netherlands, 1906–1907
- Quarr Abbey, Isle of Wight, 1907–1911
- At Comines, the church of Saint Chrysolus was built from 1925 to 1929 in collaboration with Maurice Storez.
- At Audincourt, the church of Notre-Dame de l'Immaculée Conception, 1932, was an early building in reinforced concrete.
- At Solesmes Abbey, the new library, the gallery of the great cloister and the lavatorium
- The chapel of the seminary of Saint Louis, on the domain of Saint Hubert, Neuvy-sur-Barangeon, Cher, 1936
- At Suresnes in the garden city, the church of Notre-Dame de la Paix was dedicated in 1936.
- Basilica of Saint-Joseph-des-Fins at Annecy
- The Priory of Saint Bathilda at Vanves, between 1934 and 1936
- The Château du Grand Chavanon in Neuvy-sur-Barangeon, between 1935 and 1937.
- The church Nossa Senhora da Conceição in Porto, Portugal, 1939–1947
- In Saint-Benoît-du-Lac, the Saint Benedict Abbey
- In Montreal the completion of the exterior of the basilica of Saint Joseph's Oratory.
- François Brault and Guy L. Coté made a film about Dom Bellot at Quebec in 1987: Dom Bellot, architecte, 1876–1943.