To assess the impact of a school-based health intervention on adolescents' health knowledge, psychosocial assets and health behaviors, including comparisons of implementation mode: remote, hybrid or in-person. The Stanford Youth Diabetes Coaches Program, an 8-week, school-based health promotion and coaching skills program, was offered to adolescents (ages 14--18 years) from four low-income US communities. Mode of program implementation was remote, hybrid or in-person. Participants completed online pre- and postsurveys. Analysis included paired t-tests, linear regression and qualitative coding. From Fall 2020 to Fall 2021, 262 adolescents enrolled and 179 finished the program and completed pre- and postsurveys. Of the 179, 80% were female, with a mean age of 15.9 years; 22% were Asian; 8% were Black or African American; 25% were White; and 40% were Hispanic. About 115 participants were remote, 25 were hybrid and 39 were in-person. Across all participants, significant improvements (P < 0.01) were reported in health knowledge, psychosocial assets (self-esteem, self-efficacy and problem-solving) and health behaviors (physical activity, nutrition and stress reduction). After adjusting for sex and age, these improvements were roughly equivalent across the three modes of delivery. Participation was associated with significant improvements in adolescent health behaviors. Furthermore, remote mode of instruction was just as effective as in-person and hybrid modes.