Belly was born at St. Omer, in 1827. He studied under Troyon, and in 1849 visited Barbizon where he came under the influence of Théodore Rousseau.
In 1850–1 he travelled to Greece, Syria, and the Black Sea. In 1853 he made his debut at the Paris Salon, exhibiting four landscapes of Nablus and Beirut, and of the shores of the Dead Sea, which attracted critical acclaim. In 1855–6 he visited Egypt, travelling up the Nile in the company of another painter, Edouard Imer. A second trip to Egypt in 1856 was largely spent making studies for his painting Pilgrims going to Mecca, now in the Musée dOrsay.
As well as his paintings of Middle Eastern subjects he painted portraits and landscapes of Normandy and the Sologne throughout his career, and in 1867 bought land at Montauban. He died in Paris in 1877.