<p>Engineering graduates are called on by society to work with others to address wicked problems which incorporate a wide range of socio-technical considerations. One promising approach to more wholistically prepare students for the demands of engineering-related work and positively contributing as citizens is community-engaged learning. To help this pedagogy more closely meet its full potential, this study used the context of Engineers Without Borders USA (EWB-USA), as viewed through the lens of its alums in professional practice. It also explored individuals’ differentiated outcomes produced by the many types of variation inherent in the EWB-USA model. The goal of the project was to inform best practices for how community-engaged engineering programs can be implemented to support students’ professional preparation. This study took a QUAN QUAL explanatory sequential mixed-methods approach. The survey instrument (<em>n</em> = 268) led to non-parametric tests for group comparisons which were conducted on scores generated through exploratory factor analysis. Inductive thematic analysis was then used on the semi-structured interview transcripts (<em>n</em> = 29). EWB-USA was shown to support the transition between schooling and work through authentic experiential learning, which incorporated inherently-complex projects truly intended for implementation to meaningfully benefit end-users and engaging with a wide range of diverse stakeholders. It especially bolstered the development of competencies in project management, design and project processes, communication, diverse teaming, contextualization, addressing challenges and new situations, and functioning as a connected element of larger complex socio-technical systems. These gains were reflected in the alums’ perceived advantage in career outcomes, demonstrating their long-lasting transferability to professional practice. The results of this study also showed that while limited variations were found based on participant demographics, differences in personal experience within EWB-USA had a greater effect on outcomes. The differences found based on demographic groupings consisted of women reporting greater benefits to their confidence and sense of community. Impactful individual experience differences identified included length of time involved with EWB-USA, mentor engagement, leadership opportunities, repeating phases on different projects, seeing a project from start-to-finish, and number of trips taken to the community partner site. Across the competencies developed from the program, alums often reported perceiving greater benefits from their EWB-USA experiences once they had an opportunity to apply their learnings in professional practice.</p>