In 1940 De Sica acts as director after having grabbed all the secrets of the set. His first films were Red Roses (1940), Maddalena Zero for Conduct (1940), Doctor Beware (1941) and A Garibaldian in The Convent (1942). However, thanks to his Children Are Watching Us (1943), De Sica established himself as a sensitive and busy director. In the postwar period of the Italian cinema, thanks to the collaboration with Cesare Zavattini, De Sica succeeded in expressing his best. He entered with full rights among the directors of the neorealism thanks to films like Shoeshine (1946), The Bicycle Thief (1948), Miracle in Milan (1951), Umberto D. (1952), in which there is a clear social denunciation.

De Sica's neorealist style is very different from Roberto Rossellini's experimental film style. De Sica's style represents a mixture of some characteristics that film historians usually associate with neorealism, such as non-professional actors, real locations and social themes. One of De Sica's most individual characteristics, such as ability in directing children or non-professionals, may be explained more by his own personality as a matinee idol actor in fascist Italy. He was also keen to understand the skill of screen acting from personal experience rather than abstract neorealist principle like the theory that only non-professionals are 'realistic'