Throughout the years, studies had documented the influence of grit, academic adjustment, and happiness on college students' academic performance. However, none of the previous studies warrant conclusive results. Previous findings yielded inconsistent conclusions. In effect, the predictive ability of grit, academic adjustment and happiness on academic performance still merit further investigation, especially among freshmen students. This paper had taken the route towards exploring how grit, academic adjustment, and happiness predict first-year students' academic performance. The study was conducted at Central Luzon State University where 313 freshmen students participated. The correlational analysis found several surprising findings. First, both grit and college adjustment was not significantly related to freshmen students' academic performance. Happiness was the only significant predictor of academic performance. Second, the findings show that grit, academic adjustment, and happiness were significantly inter-correlated. The present investigation may suggest that the predictive ability of happiness on academic performance may be dependent on the influence of grit and college adjustment. This may further imply that the grittier the students, the more capable they are in adjusting with their academic life, the happier they become, and the higher academic performance they achieve. The theoretical and practical implications of the findings are discussed.