The present study revisited the unresolved issue of the long-term effects of part-time working intensity during high school on students' achievement, participation in postsecondary education, time allocation, and work-related values and expectations. Using data from the Educational Longitudinal Study of 2002 (N = 14,654), the effects of part-time working in Year 12 on outcomes assessed at graduation from high school and 2 years later were studied with propensity score methods for categorical treatments. Three theoretical perspectives on the effects of part-time working intensity (subversion of academic goals, character building, threshold model) were contrasted. Substantively, there were negative linear effects of working intensity on achievement outcomes. Results for higher education participation partly supported a threshold model. Heterogeneous effects for self-reported time use and work-related values suggested that the negative effects on achievement outcomes were not due to a simple zero-sum game. Ironically, working with high intensity led students to value having a good job more strongly but might undermine their chances of achieving this goal. However, these effects were only recognized 2 years after high school graduation, when occupational expectations were negatively affected by working intensity in Year 12.