Technology-enabled learning (TEL) environments are increasingly central to contemporary education, yet their effectiveness is often assessed using engagement or satisfaction metrics rather than durable cognitive outcomes. This study investigates how TEL instructional design features Microlearning Quality, Gamified Engagement, and Adaptive Personalization shape learners’ Knowledge Retention while incorporating the psychological mechanism of Perceived Usefulness and the moderating influence of Personality Traits. A quantitative cross-sectional survey was conducted with 210 learners experienced in digital learning systems. Data were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM) to test an integrated framework linking instructional design, perception, and individual differences. Results indicate that all instructional features significantly enhance knowledge retention both directly and indirectly through perceived usefulness. Microlearning Quality emerged as the strongest predictor, emphasizing the cognitive value of structured and modular content delivery. Perceived usefulness acts as a key psychological mediator that converts instructional design into sustained cognitive investment. Personality traits specifically openness to experience and conscientiousness strengthen the relationship between perceived usefulness and retention, demonstrating that learner psychology amplifies instructional effectiveness. The model explains a substantial proportion of variance in retention, confirming strong predictive power. The findings extend technology acceptance theory into the domain of cognitive performance and highlight that digital learning effectiveness depends on the alignment between instructional quality and learner characteristics. The study offers theoretical and practical insights for designing TEL systems that prioritize durable knowledge outcomes rather than temporary engagement..