Objective: The COVID-19 pandemic's effects on college student mental health and its underlying mechanisms are not fully understood. Although necessary, physical distancing abruptly restricts interaction with environmental rewards and disrupts sleep patterns, both of which may contribute to psychological symptoms (eg, depression and anhedonia). This study explored differences in psychological symptoms, reward exposure and responsiveness, and sleep before versus during the pandemic. Methods: Eighty-seven college students completed baseline questionnaires and a one-week daily diary paradigm. The sample was divided into two groups based on data collection before (pre-) or after (post-COVID-19) implementation of state-wide COVID-19 physical distancing measures. Results: Findings highlight higher anhedonia, decrements in exposure to social, professional, and exercise related rewards, lower anticipatory reward responsiveness, and lower sleep efficiency among college students during the initial months of the pandemic. Conclusions: Findings suggest anhedonia, reward system functioning, and sleep may be important targets to mitigate against college student mental health sequelae during COVID-19.