Teacher leaders play a significant role in school and system improvement. Teacher leaders who maintain teaching responsibilities while taking on leadership responsibilities outside the classroom require professional learning. A school district worked with university faculty and professional learning facilitators to develop a design-based professional learning program (DBPL) as part of a design-based research study. Two research questions guided the study: (1) In what ways does DBPL support teacher leaders' efforts in creating the collective collaborative capacity? (2) What is needed for teacher leaders to develop collective collaborative capacity? Teacher leaders (n = 374/500) completed a pre- and post-survey, provided artefacts, contributed to online collaborative conversations, and provided written feedback. Four findings emerged from this study; teacher leaders: (1) increased in leading teacher learning, using resources, understanding school authority goals and leadership expectations, and expanding their professional network; (2) increased in their ability to lead collaboration in their professional learning community; (3) developed trusting relationships within the network of learning leaders; and (4) required a shared or distributed approach at the school level. DBPL empowered teacher leaders to exercise leadership by taking on leadership responsibilities outside of the classroom with a deliberate focus on creating coherence by developing collective responsibility for student success.