Objective The purpose of this study was to examine the relationship of grit as a construct representing perseverance to overcoming barriers and the total number of school absences to academic performance (AP) while controlling for sociodemographics, fitness (i.e., PACER), and Body Mass Index (BMI). Methods Adolescents (N = 397, SD = 1.85; 80.9% females; 77.1% Hispanic) from an urban, minority-majority city in the Southern United States completed the FitnessGram® assessment of physical fitness (e.g., aerobic capacity and Body Mass Index (BMI)) and the valid and reliable short grit survey. The schools provided sociodemographics, attendance, and AP data for the adolescents. Results Adolescents with higher grit scores (rs = 0.21, P < 0.001) and less total absences (rs = −0.35, P < 0.001) performed better on AP. Hierarchical multiple regression indicated that grit and absences were associated with AP (β = 0.13, P < 0.01 and β = −0.35, P < 0.001, resp.). Conclusions Grit and a total number of absences are significant contributors to academic success, particularly among Hispanic adolescents. Further, grit and school attendance may serve as a better measure of protective factors over proximal health measures of cardiovascular health and BMI.