Emil Ludwig (originally named Emil Cohn) was born in Breslau, now part of Poland. Ludwig studied law but chose writing as a career. At first he wrote plays and novella, but also worked as a journalist. In 1906, he moved to Switzerland, but, during World War I, he worked as a foreign correspondent for the Berliner Tageblatt in Vienna and Istanbul. He became a Swiss citizen in 1932, later emigrating to the United States in 1940.

At the end of the Second World War, he went to Germany as a journalist, and it is to him that we owe the retrieving of Goethe's and Schiller's coffins, which had disappeared from Weimar in 1943/44. He returned to Switzerland after the war and died in 1948, in Moscia, near Ascona.

During the 1920s, he achieved international fame for his popular biographies which combined historical fact and fiction with psychological analysis. After his biography of Goethe was published in 1920, he wrote several similar biographies, including one about Bismarck (1922–24) and another about Jesus (1928). As Ludwig's biographies were popular outside of Germany and were widely translated, he was one of the fortunate émigrés who had an income while living in the United States. His writings were considered particularly dangerous by Goebbels, who mentioned him in his journal.

Emil Ludwig interviewed Benito Mussolini and on December 1, 1929 Mustafa Kemal Atatürk. His interview with the founder of the Republic of Turkey appeared in Wiener Freie Presse in March 1930, addressing issues of religion and music. He also interviewed Joseph Stalin in Moscow on December 13, 1931. An excerpt from this interview is included in Stalin's book on Lenin. Ludwig describes this interview in his biography of Stalin.

Ludwig's extended interviews with T.G. Masaryk, founder and longtime president of the Czechoslovakia, appeared as Defender of Democracy in 1936

The following French editions of Emil Ludwig's books were published in the period 1926–1940: Biographies: Goethe (3 volumes), Napoléon, Bismarck, Trois Titans, Lincoln, Le Fils de l'Homme, Le Nil (2 volumes). Political works: Guillaume II, Juillet 1914, Versailles, Hindenburg, Roosevelt, Barbares et Musiciens, La Conquête morale de l'Allemagne, Entretiens avec Mussolini, La Nouvelle Sainte-Alliance.

Biographies of Goethe, Napoleon, Bismarck and Wilhelm Hohenzollern are available in English from G. P. Putnam's Sons (New York and London).

Emil Ludwig was...and remains...renowned for a popular biography of Napoleon published in English in 1926, just after it was published in Germany in the original German, while Ludwig was still living there. This book is still quite readable today - Ludwig has a rare gift of evoking a vanished era in straightforward plain prose. The book has a rare quality of immediacy, as if what Ludwig writes of were almost current history. Napoleon was published by a New York publishing house renowned for titles of intellectual and scholarly interest in its day, Boni and Liveright.