In 1935, the Museum of Modern Art (MoMA) incorporated film into a museum collection for the first time. During MoMA screenings in the 1930s, the film department drew a symbolic line between cinema as art and as entertainment, a continuing effort until today. Based on ethnographic research, in this paper I examine four practices that sustain film as art at the museum: 1) the establishment of rules of conduct and uses of design and technology, 2) membership, 3) surveillance, and 4) tacit curatorship. At MoMA, institutional actors and audiences alike engage in practices to experience the moving image as art. The centrality of institutions in processes of artistic legitimation have been thoroughly studied, but what happens inside art organizations has received less attention. I contend that a micro-sociological framework of artistic legitimation reveals novel aspects of how a milieu of practices and actors—including zealous audiences’ active role—sustain film as art in organizations such as MoMA.