College students are one of the top at-risk groups for chronic sleep loss and poor sleep quality, therefore research devoted to the identification of cognitive, attitudinal, and behavioral predictors of sleep is essential. The present study examined predictors of both self-reported and actigraphic measures of sleep quality and quantity, as well as tested direct and indirect associations of sleep with salient physical and mental health outcomes within a sample of American college students (N = 142). Results demonstrated that attitudes but not knowledge predicted self-reported sleep duration, self-reported sleep quality, sleep hygiene behaviors, and actigraphic measures of weekday and weekend sleep duration. In turn, self-reported sleep quality predicted subjective well-being and depression, and sleep hygiene yielded indirect effects via sleep quality. Actigraphic measures of sleep duration predicted body mass index, while actigraphic measures of sleep efficiency, a component of sleep quality, predicted diastolic blood pressure and depression. Sleep hygiene yielded indirect effects on blood pressure via sleep efficiency. Results shed light on the predictive validity of attitudes towards sleep and sleep hygiene, as well as inform application efforts targeting the improvement of sleep and health outcomes among the college population.