This study examines the effectiveness of the Center for Civic Education's Project Citizen teacher professional development program and curriculum intervention in producing positive student learning outcomes that support civic engagement. Through Project Citizen, students identify and research a problem in their community, explore solutions, consult with stakeholders, and develop an action plan. A three-year national study was conducted by the Civic Education Research Lab at Georgetown University from 2020-2023, during the height of the COVID-19 pandemic. The research employed randomized controlled trials of middle and high school students enrolled in Project Citizen and control group students who took a conventional civics class. The study confirmed the efficacy of project-based learning conveying civic skills and orientations conducive to civic engagement. Project Citizen students' problem-solving and civic expression skills improved significantly after the intervention. They reported a greater desire to turn out to vote if given the opportunity and felt better prepared to take part in the civic life of their community. The gains in civic skills and propensity for engagement were greater for Project Citizen students than those in the control group.