Introduction: Organized activities practiced in adolescence are known to foster positive development, including active citizenship. Active citizenship encompasses a wide range of behaviors, one of them being pro-environmental behaviors. Few studies focused on the developmental factors that may predict these behaviors in adults, despite their crucial role in counteracting the current climate crisis. However, prior research showed that attitudes were typically major predictors of behaviors. This study thus tested a model that posited participation in organized activities in adolescence as a predictor of pro-environmental attitudes in emerging adulthood and these attitudes as a predictor of pro-environmental behaviors in adulthood. Methods: Three hundred twenty-one participants (61% girls) from Quebec (Canada) completed all time points across a 17-year period. Participants self-reported their participation in organized activities (sports, cultural, prosocial) from ages 14 to 17, pro-environmental attitudes, from ages 18 to 22, and pro-environmental behaviors, at age 30. Results: Results revealed that pro-environmental attitudes mediate the relationship between adolescent participation in cultural activities and pro-environmental behaviors in adulthood. Practicing sporting or prosocial activities in adolescence did not predict stronger pro-environmental attitudes or behaviors. Interestingly, pro-environmental attitudes consistently predicted pro-environmental behaviors later in life. Conclusions: These findings and prior research suggest participation in cultural activities may provide a space to discuss, imagine change, and cultivate sensitivity towards nature. This may contribute to the development of pro-environmental attitudes and behaviors later in life.