Early employment in the family business of stock brokerage in Germany and Paris gave way to an interest in art collecting while Kahnweiler was still in his twenties.

Kahnweiler's appreciation of Picasso's talents was especially gratifying to the artist, since he was largely unknown and destitute at the time when many of his most famous works were created.

[1] In his gallery, Kahnweiler supported many of the great artists of his time who found themselves without adequate recognition and little or no interest among collectors.

As a businessman, Kahnweiler pioneered many new methods of working with artists and art dealing; these are now established practices in the industry.

He expanded his presentations by bringing together artists, writers and poets to produce their works as a joint project in more than 40 books.

As a publisher of art with literary works, he had no equal, and was the first to sponsor publications by Max Jacob, Guillaume Apollinaire, André Masson, Gertrude Stein, Pablo Picasso, and many others.

Kahnweiler's entrepreneurial abilities were so acute that by the 1950s his art gallery was among the top 100 French companies in terms of export figures.

From the viewpoint of the general public, Cubism came to be more associated with the 'Salon Cubists', such as Jean Metzinger,[3] Albert Gleizes, Fernand Léger, Robert Delaunay, Henri Le Fauconnier, Marcel Duchamp and Francis Picabia.

[4] The outbreak of World War I in 1914 not only ruptured the Cubist experiments in art, but also forced Kahnweiler to live in exile in Switzerland; due to his German citizenship, he was considered an alien under French law.

Many German nationals living in France had their possessions sequestered by the French state, and as a result, Kahnweiler's collection was confiscated in 1914 and sold by the government in a series of auctions at the Hôtel Drouot between 1921 and 1923.

[7] During the years of exile (until 1920), Kahnweiler studied and wrote works such as the Der Weg zum Kubismus and Confessions esthétiques.