Background: Within goal contents theory, the goals that people pursue are differentiated into two categories: intrinsic goals (IGs) and extrinsic goals (EGs). Based on theory, prioritizing IGs relative to EGs supports greater psychological outcomes. We examined how exercise-specific IGs and EGs can jointly predict psychological wellbeing, health-related quality of life, life satisfaction, vitality and affect in youth. Methods: We used polynomial regression analysis with response surface methodology to analyze data from 400 youth (59.8% female; Mage=15.9±.31 years) collected via questionnaires completed on two occasions (6 weeks apart) as part of a wider study. Results: Based on the regressions, IGs were positively associated with all outcomes (betas=.17 to .36, ps<.05), whereas EGs were negatively associated with all outcomes (betas=-.29 to -.36, ps<.05) except psychological wellbeing (beta=-.05, p=.53). Based on the response surface values, psychological wellbeing was higher when the degree of agreement between IGs and EGs increased (a1-a2 ps<.05), and health-related quality of life, life satisfaction, vitality and affect were higher when IGs were greater than EGs (a3 ps<.05). Also, for participants with greater EGs than IGs (i.e., negative differentiation), affect and psychological wellbeing were better when the difference between the two was smaller (a4 ps<.05). Conclusions: IGs were associated with better outcomes, and EGs were associated with poorer outcomes. Yet, considering the degree of agreement and the direction of differentiation between IGs and EGs within polynomial regression analysis with response surface methodology provided new insight into the conjoint influence of IGs and EGs on perceptions of life satisfaction and wellbeing.