This study focused on first-semester college students, investigating (a) indirect effects of aggregate alcohol use on grade point average (GPA) through academic effort (skipping class and time on schoolwork) and (b) daily effects of alcohol use on reduced effort. Eighty students reported daily alcohol use and academic effort (skipping class and hours spent on schoolwork) during five selected weeks of their first semester; the university provided GPAs. We found strong evidence of an indirect effect of aggregate alcohol use on GPA through skipping class; there was weaker evidence for time on schoolwork as a mediator. Daily analyses showed increased skipping and reduced schoolwork on days during which students used alcohol. Intervention to increase persistence may focus on reducing alcohol use and on dealing with low effort (e.g., skipping class).