Contributions: The study contributes to the social cognitive career theory (SCCT) by explaining high-school students’ career choices and finding possible relations between self-efficacy, interpersonal skills, what inspires them to choose a career, and their actual choices. The practical contribution of this research lies in understanding the impact of the For Inspiration and Recognition of Science and Technology (FIRST) program on its participants and graduates. Background: The FIRST program incorporates project-based learning that fosters the design and production of innovative robotics by teams of students who compete annually. Research Questions: 1) Do the FIRST program activities increase STEM exposure and encourage STEM career choices, and if so, how? 2) What are the factors that affect these choices? Are there correlations between those factors? If so, what are they? 3) Is the effect of the FIRST program on FIRST high-school students’ exposure and career choices different from that effect on FIRST graduates? If so, what are the differences and does gender play a role in these differences? Methodology: The research participants included 119 FIRST high-school students and 297 FIRST graduates. The research applied a convergent parallel mixed-methods approach, with data collected both qualitatively via interviews and quantitatively via questionnaires. Findings: Analysis of the data showed that the FIRST program increased participants’ STEM exposure and career choice in STEM domains. A significant, positive, strong correlation was found between interpersonal skills, STEM exposure, career choice, family and school support, and external motivation.