Once he was fit to resume normal life outside the health care system, he settled in Prague and made his living taking photographs on commission, to supplement his disability pension. He met Czech Avant-Garde photographer Jaromír Funke, who became his good friend, and joined the Amateur Photography Club. In 1922, he began formal education in his new vocation at the Prague-based School of Graphic Arts. His teachers, leading "traditionalist" Czech photographers such as Karel Novák, introduced him to the most influential American photographer of the twentieth century, Edward Weston, and his soft focus Pictorialism. But it was largely the work of Clarence White, who employed light and shadow to evoke a three dimensional mood and a virtual glow from the highlights, that can be discerned in Sudek's early work. Sudek also co-founded professional associations such as Photoclub Prague and the Czech Photographic Society.

Along with the other leading young photographers, he soon rejected the traditional—"painterly"—approach and embraced the modernist views. For this, he and Funke were dismissed from Photoclub Prague. In response, they rallied photographers who shared their modernist views, and in 1924, formed the "Avant-Garde Czech Photographic Society".

The Nazi invasion of 1939 brought much of the cultural life of Prague to a halt; likewise, Sudek took a step back to reflect on his work—and discovered contact prints. He almost gave up on the negative and pushed the boundaries in the uses of printing papers and effects instead. At that time, the ideal of printing, particularly in America, was manifested by "straight photographers" such as Ansel Adams. Sudek distanced himself from this technique and began using very dark and often low contrast images.

The intense beauty and authenticity of the stone brought out by this method convinced him that it would be best to make only contact prints. He realized that it was an all-powerful tool that would allow for presenting detail as a broad spectrum of tone, which is what he desired. This also meant that he would have to dedicate himself fully to his artistic passion and maintain a high standard of craftsmanship. From then on he carried view cameras as large as the 30 x 40 cm format (12 x 16 inches), operating the equipment propped in his lap with one hand, and what one hand could not handle, the teeth would.

Almost all of his subsequent work—commercial and personal—was contact prints from negatives. The pictures often relied on limited tonalities; they were dark and sombre and very subjective, as if the lives of his subjects, human or not, were to be sheltered from the outside world. The critics hammered him for this drifting away from the norm.

Sudek's own stylistic and emotional peculiarities overrode the styles prevalent during his life. Being a loner, he produced a vast number of his photographs out of his studio window, which acted as a reflective backdrop, framing artfully arranged objects such as onions, pebbles, or flowers. Those were his homage to the carefully arranged still-lifes of Jean Baptiste Simeon Chardin and the Old Dutch masters. Even though the setting was the same, Sudek would make each of the photos distinct and unique with the aid of atmospheric conditions, such as dew, ice, or rain drops.