This dissertation focuses on what drives efforts, particularly venture efforts of early-stage entrepreneurs. To understand the psychological processes that move entrepreneurs to exert effort, I propose a process model of motivation incorporating affect and cognition. Specifically, I examine the dynamic relationships among affect, cognition, and effort of the individual entrepreneur over time. Effort is conceptualized as a dynamic construct that fluctuates, yet most empirical studies depict effort as static rather than dynamic. Although scholars acknowledge affective influences on behaviors through cognitive processes, the nature of the affect-effort link remains unclear. In addition, there is a dearth of process-oriented research in entrepreneurship. Process-oriented studies are critical because entrepreneurship is a process unfolding over time. Through this dissertation, I attempt to address the abovementioned research gaps by examining how variations in the entrepreneur’s affect and cognition predict venture effort fluctuations using a longitudinal, within-individual approach. I conducted an experience sampling study involving over a hundred early-stage entrepreneurs in business incubators. Participants reported on their positive and negative affect, perceived goal progress, temporal focus, and venture efforts using their cell phones twice daily for four consecutive days, every other week, over the course of three months. The results provided support for the hypothesized within-individual relationships of positive affect and perceived goal progress, as well as positive affect and future temporal focus. The mediating effects of perceived goal progress and future temporal focus on positive affect and venture efforts also obtained support. The relationships between negative affect and the cognitive factors of perceived goal progress and present temporal focus were not supported. Data provided support for the moderating effects of self-efficacy on the relationship between present temporal focus and venture efforts, while the moderating roles of mood labeling and goal commitment were not supported. Theoretical and practical implications of the study on work motivation literature and entrepreneurship research are discussed.