[1] His father, the sugar millionaire William Hood Stewart, moved the family from Philadelphia, Pennsylvania to Paris in 1865, and became a distinguished art collector and an early patron of Marià Fortuny and the Barbizon artists.

Julius studied under Eduardo Zamacois as a teenager, under Jean-Léon Gérôme at the École des Beaux-Arts, and later was a pupil of Raymondo de Madrazo.

[2] Stewart's family wealth enabled him to live a lush expatriate life and paint what he pleased, often large-scaled group portraits.

The most accomplished of these, On the Yacht "Namouna", Venice (Wadsworth Atheneum, 1890), showed a sailing party on deck and included a portrait of the actress Lillie Langtry.

[3] Late in life, he turned to painting outdoor nudes and Venetian scenes, but Stewart is best remembered for his Belle Époque society portraits.