Leonetto Cappiello was an Italian poster art designer who lived in Paris.  He is now often called "the father of modern advertising" because of his innovation in poster design.  The early advertising poster was characterized by a painterly quality as evidenced by early poster artists Jules Chéret, Alfred Choubrac, and Hugo D'Alesi.  Cappiello, like other young artists, worked in way that was almost the opposite of his predecessors.  He was the first poster artist to use bold figures popping out of black backgrounds, a startling contrast to the posters early norm.

Cappiello had no formal training in art.  The first exhibition of his work was in 1892, when a painting was displayed at the municipal museum in Florence.

Cappiello started his career as a caricaturist illustrating in journals like Le Rire, Le Cri de Paris, Le Sourire, L'Assiette au Beurre, La Baionnette, Femina, and others.  His first album of caricatures, "Lanterna Magica," was made in 1896.  In 1898, he moved to Paris, and his caricatures were published in Le Rire for the first time.

In 1902, a 24-page book of his caricatures was published entitled Gens du Monde ("people of high society") for the magazine L'Assiette au Beurre.  The following year a 38-page book entitled Le Théâtre de Cappiello ("the theatre of Cappiello") was published for a special issue of Le Théâtre magazine, this included captions written by theatre critics.  Cappiello began to move away from caricature work favouring posters.  In 1905, a final publication, 70 Dessins de Cappiello ("70 drawings by Cappiello") by H. Floury, included black and white lithographic prints, as well as a handful of color images produce by the process of pochoir.  The technique was popular at the time as a way of adding color to an image relatively cheaply, and would involve color being hand-painted onto an image with stencils.

Cappiello made his name during the poster boom period in the early 20th century, with designs markedly different from premier poster artist Jules Chéret.  His first poster, for the newspaper Frou-Frou, was made in 1899.

Cappiello's career as a poster artist began in earnest in 1900 when he began a contract with the printer Pierre Vercasson.  In this period, the printers would act as an agent for artists and commission work to them.  Vercasson had a print house, and his goal was to bring vibrant and color to the streets of Paris, he wanted the posters that he produced to stand out from the rest and attract lucrative new advertisers to his agency.  Of course living in Paris, he was aware of the current art scene, and had seen many examples of Cappiello's work, including a small number of posters already produced and in particular those for Le Frou-Frou.  He knew that Cappiello had the potential to be exactly what he was looking for.  The relationship commenced with the arrangement that Vercasson would find the clients and brief Cappiello on the product.  It was then up to Cappiello to produce a sketch for the client for which he would receive the fee of 500 francs, a good amount at the time.  Once the design had been approved by the client, a full-size design would be produced for the poster at a size of 1 x 1.4m, an old French paper standard known as the Double Grand Aigle.  Cappiello would also be responsible for ensuring the successful transfer of the design onto lithographic stone ready for printing.

He was married to Suzanne Meyer Cappiello in 1901, and his brother Oreste was married to Camille, sister of the painter Alfredo Müller.

Between 1901 and 1914, he created several hundred posters in a style that revolutionised the art of poster design.  Cappiello redesigned the fin-de-siècle pictures into images more relevant to the faster pace of the 20th century.  During this period, Capiello continued as a caricaturist.

During World War I, Cappiello worked as an interpreter in Italy.  After the war, Cappiello returned to producing posters.  In 1919, he began working with a new publisher, Devambez, indicating the second period in his career.  Unlike Vercasson, Devambez did not have its own print house, and had the posters printed at a number of large printers.  The agency concentrated on finding new clients from across Europe, and successfully spread Cappiello's celebrated works across the continent.  He remained with the agency until 1936.

Over the course of his career Cappiello produced more than 530 advertising posters which would surprise and delight the viewer.  Today, his original posters are still collected, sold at auction, and by dealers around the world.