COVID-19 underscores the importance of understanding variation in adherence to rules concerning health behaviors. Children with conduct problems have difficulty with rule adherence, and linking early conduct problems with later adherence to COVID-19 guidelines can provide new insight into public health. The current study employed a sample (N = 744) designed to examine the longitudinal consequences of childhood conduct problems (Mean age at study entry = 8.39). The first objective was to link early conduct problems with later adherence to both general and specific COVID-19 guidelines during emerging adulthood (M age = 19.07). The second objective was to prospectively examine how interactional (i.e., callous unemotional traits, impulsivity) and cumulative (i.e., educational attainment, work status, substance use) continuity factors mediated this association. The third objective was to examine differences in sex assigned at birth in these models. Direct associations were observed between childhood conduct problems and lower general, but not specific COVID-19 guideline adherence. Conduct problems were indirectly associated with both general and specific adherence via higher levels of callous unemotional traits, and with specific adherence via higher problematic substance use. No differences in the models were observed across sex assigned at birth. Findings provide insight into both how developmental psychopathology constructs are useful for understanding COVID-19 guideline adherence, and the ways in which conduct problems may shape health outcomes.