Background: There is a growing emphasis on integrating engineering design into K-12 science, technology, engineering, and mathematics (STEM) education. Prior studies have primarily examined the impact of engineering design on student learning outcomes or employed frequency-based static statistical analyses, rather than focusing on student learning processes--that is, what students actually did and thought during engineering design courses. Purpose/Hypotheses: This study explored the effects of two prominent engineering design approaches, forward and reverse, on learning outcomes and learning processes. Design/Method: A mixed-methods quasi-experiment was conducted with a purposive sample of 52 11th-grade students enrolled in a mechatronics engineering design course. One class engaged in the forward engineering teaching condition (F-class; n = 28) and the other in the reverse engineering teaching condition (R-class; n = 24). Results: Mann-Whitney "U" tests indicated that the two conditions exhibited no significant differences in overall design solutions. However, the R-class surpassed the F-class in understandability and organic qualities, using the creative product analysis matrix. The Mann-Whitney U test showed that the R-class scored significantly higher on mechatronics content knowledge than the F-class. Lag sequential analysis and epistemic network analysis revealed distinct differences in engineering design behavior, engineering design reflection, and cognitive action between the conditions. Conclusions: These findings underscore the importance of applying multiple analytical lenses to examine outcomes and processes in engineering design learning. They offer practical implications for developing secondary-level engineering design curricula that support students' design solutions, conceptual understanding, design behavior, design reflection, and higher order cognitive action.