Introduction: The association between physical activity levels and digital habits has garnered interest, particularly in the context of the COVID-19 pandemic. This study aimed to elucidate this association among secondary school students in Warsaw, Poland. Materials and Methods: This cross-sectional investigation used a questionnaire to assess physical activity, intensity of device use, and two sub-scales of digital hygiene. The sample consisted of 629 students aged 15-19. Results: 31% of students reported high levels of physical activity, 27.7% indicated proficient control over screen time, and 33.1% demonstrated effective notification management. Statistical analysis revealed that moderate to high levels of physical activity were associated with increased likelihood of disciplined screen time (OR for moderate = 2.351, 95% CI [1.335-4.139]; OR for high = 3.933, 95% CI [2.205-7.015]). Device overuse was inversely related to screen time management (OR for not overusing = 13.983, 95% CI [7.546-25.909]; OR for average use = 5.748, 95% CI [3.083-10.717]). Conclusions: The findings underscore the importance of digital hygiene, potentially indicating a stronger correlation with screen time management than physical activity alone. Interventions should take it into account to foster a holistic approach to healthy lifestyle habits in young populations.