[1] The son of Jacques Seligmann, a German-born French and American antiquarian and art dealer, Seligman was raised in Paris in the luxurious Hôtel de Monaco.
He frequently joined his father on business trips including a one to St. Petersburg in 1910 in connection with the acquisition of the Swenigorodskoi enamels.
In 1923, on the death of his father, he became president of both the Paris and New York interests, changing the name back to Jacques Seligmann & Cie.[1][2] Seligman developed a strong interest in modern art for the New York gallery, dealing in works by Pierre Bonnard, Paul Cézanne, Honoré Daumier, Edgar Degas, Henri Rousseau, and Vincent van Gogh but in the face of resistance from other members of the family turned to César Mange de Hauke who had studied art in England and France and arrived in the United States in 1926.
Works by Amedeo Modigliani, Odilon Redon, Ker-Xavier Roussel and Édouard Vuillard were exhibited and sold in New York.
Soon coverage was extended to Paul Cézanne, Jacques-Louis David, Eugène Delacroix, Jean Ingres, Pierre-Auguste Renoir, and Georges Seurat.
[4] As a result of the successful new business strategy, the other family members withdrew their opposition and Jacques Seligmann & Co., Inc. adopted Seligman's evolving preferences.
In November 1942 Jackson became acting director of the gallery when Paul Gardner was commissioned as a major in the US Army, to become one of the famed Monuments Men in North Africa and Europe.
Seligman began writing in the 1940s, publishing a monograph on Roger de La Fresnaye in 1945 and one on The Drawings of Georges Seurat in 1947.