After his studies at the Brussels Academy, Ensor started painting rather traditional way. His early works were of traditional subjects: landscapes, still lifes, portraits, and interiors painted in deep, rich colors and enriched by a subdued but vibrant light. In the 1880’s, Ensor style changed to a mixture of symbolism and expressionism. He also co-founded the avantgardist art group "Les vingt". He took his subject matter principally from Ostend’s holiday crowds, which filled him with revulsion and disgust. Portraying individuals as clowns or skeletons or replacing their faces with carnival masks, he represented humanity as stupid, smirking, vain, and loathsome. At age 18, James Ensor painted his most known work "Christ’s Entry Into Brussels". This controversial painting makes fun with the entry of Christ in Jerusalem. In 1892, Ensor’s art went through some more changes. Though he still made extensive use of his famous masks, Ensor decided to use pastel colours. In 1920 Ensor also wrote the music for the ballet "La Gamme d’Amour". James Ensor was made a Baron in 1930 by the Belgian king. He died in 1949 in Ostend, where there is now a museum devoted to his work.
In 1995, the state of Belgium recognized Ensor’s achievements by dedicating the 100-franc bill to him and his work.