Background: Project-based learning has shown promise in improving learning outcomes for diverse students. However, studies on its impacts have largely focused on the perceptions of students and instructors or students' immediate performance. This study reports the impact of taking a project-based introductory engineering course on students' subsequent academic success. Purpose/Hypothesis: This quantitative study examines characteristics related to enrollment in the project-based introductory engineering course and subsequent academic performance. We hypothesized that participation in the course would be associated with higher academic performance in subsequent engineering courses. In addition, we examined heterogeneity effects for students traditionally underrepresented in engineering education. Design/Method: This study utilized data on students' demographics, academic preparation, course enrollment, and course performance from 1,318 engineering students from a large public university in Southern California. Logistic regression analysis with robust standard errors examined enrollment patterns. We applied propensity scores as inverse-probability weights in multiple linear models to calculate the average treatment effect on the treated for participants from the project-based introductory engineering course in five subsequent engineering courses. This analysis was conducted for all students and for selected student subgroups. Results: Enrollment in the project-based introductory engineering course was positively associated with students' performance in some subsequent engineering courses and did not adversely affect students traditionally underrepresented in engineering. Conclusions: This study provides an example of a project-based introductory engineering course that can support students' academic success in engineering. The benefits detected for some student populations (e.g., female) are encouraging for broadening engineering pathways.