Although born in Wales, he was the son of the Marquis de Belleroche, of one of the most ancient French noble families who, being Huguenots, had fled to England in 1685.
In 1871, following the death of his father, he moved back to Paris with his family. After he had finished school there, he studied at the studio of Carolus Duran, and spent long hours copying at the Paris museums. He soon became familiar with the leading painters and intellectuals of the day, and became a founder member of the Salon d’Automne, exhibiting alongside the Impressionists and associating with Emile Zola, Oscar Wilde, Albert Moore, Renoir, Degas, Helleu and Toulouse-Lautrec. Toulouse-Lautrec and Belleroche were exact contemporaries, who first met at the age of eighteen. Belleroche painted Toulouse-Lautrec’s portrait and shared with him a passion for the model Lili, who epitomised the Belle Epoch aesthetic of Toulouse-Lautrec’s most celebrated posters. Lili became Belleroche’s favourite model and mistress.
In 1882 Belleroche also met the already acclaimed American painter John Singer Sargent, who recognised Belleroche’s talent and empathised with his free drawing style and sensitivity to light. They became life-long friends. Sargent’s handling of pastel was a great inspiration to Belleroche, while Belleroche’s sensitivity to tone and creation of form through the modeling of light exerted a strong influence on Sargent.
In 1900, Belleroche became fascinated by the medium of lithography and by 1905 he was a leading figure in the field of lithographic portraiture. A.M. Hind, a former keeper of prints at the British Museum, described his works in lithography as “amongst the greatest achievements of the craft since its discovery.”