Through an investigation into the passage of Illinois House Bill 40 in 2017, this study seeks to identify best practices to passing pro-choice legislation in state legislatures. By analyzing 39 interviews with key actors on the legislative process of HB 40, I find that three key factors contributed to the passage of HB 40: (1) the election of Donald Trump in 2016, (2) the election of pro-choice legislators and a pro-choice base in Illinois, and (3) coalitional cohesion and strategy. Considering those factors as well as evidence from 14 interviews with actors involved in abortion policy beyond HB 40, I suggest three key strategies for policy advocates to pass pro-choice abortion legislation in state legislatures: (1) take action in windows of opportunity, (2) elect a diverse base of pro-choice legislators, and (3) develop a diverse and cohesive coalition. Depending on partisan control and available resources, policy advocates may modify these strategies to maximize legislative impact. Overall, the findings of this study suggest that further academic research is necessary to evaluate the impact of coalitional and politician diversity on the political process.