This study develops an understanding of the relationships among personal accomplishment, resilience, and teaching multiple school subjects role conflict (TMSS-RC) among Irish post-primary, multi-subject teachers. A theoretically informed conceptual framework was developed to explain the relationships among personal accomplishment, resilience, and the sub-domains of TMSS-RC: status conflict, schedule conflict, and energy expenditure. Participants included 259 post-primary teachers across Ireland who were responsible for teaching physical education and at least one other school subject concurrently. Participants completed a 46-item, cross-sectional survey consisting of a demographics questionnaire, the TMSS-RC scale, the personal accomplishment subscale from the Maslach Burnout Inventory–Educators Survey, and the 10-item version of the Connor–Davidson Resilience Scale. Concurrent confirmatory factor analysis was first used to confirm the psychometric quality of the hypothesised factor structure. Results indicated that the hypothesised model was a good fit for the data. Structural equation modelling was then used to examine and verify the hypothesised relationships of the conceptual model. Results supported the model with mediation, which showed good model fit: C3(129) = 174.97, p = 0.004, χ 2/df = 1.36; root mean square error of approximation = 0.044 (90% confidence interval = 0.031, 0.057; p = 0.770), standardised root mean square residual = 0.058; non-normed fit index = 0.974; comparitive-fit index (CFI) = 0.978. Collectively, results indicate that as teachers’ levels of personal accomplishment and resilience increase, their experiences of TMSS-RC decrease. This suggests that stress as a result of teaching multiple school subjects concurrently can be reduced with an increase in teachers’ perceived levels of personal accomplishment and resiliency.