Children and teens have valuable insights to offer in the design of sociotechnical learning tools and environments. Prior work has identified a range of participatory design (PD) techniques that have been used successfully to engage youth of various ages in the design process. Less understood is how youth experience and learn from their engagement in specific PD techniques. Although recent work has begun to address this understudied area, it has focused primarily on children, not adolescents. In the current study, we document the learning opportunities experienced by a group of high school students who participated in a series of six PD sessions focusing on the design of a digital badge system that recognizes and rewards out-of-school science learning. We discuss how these learning opportunities, actualized through scaffolded reflection, contributed positively to the design of the digital badge system. This work advances knowledge of how and why engaging youth in PD can contribute to effective designs of sociotechnical learning systems.