The fungal genus Cercospora is one of the most ubiquitous groups of plant pathogenic fungi, and gray leaf spot caused by C. zeae-maydis is one of the most widespread and damaging foliar diseases of maize in the world. While light has been implicated as a critical environmental regulator of pathogenesis in C. zeae-maydis, the relationship between light and the development of disease is not fully understood. Recent discoveries have provided new insights into how light influences pathogenesis and morphogenesis in C. zeae-maydis, particularly at the molecular level. This review is focused on integrating old and new information to provide an updated perspective of how light influences pathogenesis, and provides a working model to explain some of the underlying molecular mechanisms. Ultimately, a thorough molecular-level understanding of how light regulates pathogenesis will augment efforts to manage gray leaf spot by improving host resistance and disease management strategies.