To shed light on how first-year (FY) experiences affect student well-being, the current study used Saks and Gruman's (2018) socialization resources theory to examine the mediating effect of student course engagement on the relationship between FY onboarding usefulness perceptions and changes in student satisfaction and depression. Additionally, the current study examined the effects of social integration and time pressure on student course engagement. Data were collected from 198 FY undergraduate students at two time points (1 month apart) using an online survey. Results indicated that onboarding usefulness facilitated course engagement both directly and indirectly through social integration, but time pressure did not significantly predict course engagement. Furthermore, course engagement mediated the relationship between socialization resources and changes in student outcomes of satisfaction and depression. Implications of these findings in the context of design and development of new onboarding programs as well as future research directions on FY onboarding in higher education are discussed.