At the turn of the 20th century he was an editor at the Parisian literary journal Gil Blas and a popular theatre critic. During World War I, Blum served in the Battle of the Somme. He saved threatened artwork from Amiens Cathedral and earned the French Croix de guerre.
He became director of plays and operettas at Monte Carlo in 1924, where Sergei Diaghilev"s Ballets Russes was based.
In 1931, Blum was hired by Louis II, Prince of Monaco, to create a ballet company that would continue the work and legacy of the late Diaghilev (who had died in 1929). In 1932, with the help of financier Serge Denham, Blum and Colonel West. de Basil formed the Ballet Russe de Monte Carlo.
Blum kept ballet alive in Monte Carlo. In short order, he hired choreographer Bronislava Nijinska.
After Nijinska left, Blum hired Michel Fokine.
In 1937, Blum and former Ballet Russes choreographer Léonide Massine acquired financing from Julius Fleischmann, Junior."s World Art, Incorporated. to create a new ballet company. In 1938, their new company was allowed to regain the name Ballet Russe de Monte Carlo (although the company fled for the United States in 1939, and was thereafter mostly based in New York City). Deportation and death
In the summer of 1940, after the German occupation of Paris, Blum returned to France to be with his family.
He was arrested on 12 December 1941 in his Parisian home, among the first Jews to be arrested in Paris by the French Police.
He was held in the Beaune-la-Rolande internment camp, then in the Drancy internment camp. On 23 September 1942 he was shipped to the Auschwitz concentration camp.
While at the camps, he was known for keeping up the spirits of his fellow prisoners with tales of his life in the arts He was killed by the Nazis at age 64 in late September 1942.