Gamified learning systems can enhance both learning outcomes and engagement, but research findings on the effectiveness of such systems are mixed, and there is inadequate attention to theory-grounded designs of gamified learning systems. We address these gaps by conducting a theory-grounded design, development, and evaluation of a gamified e-training system for technology learning. Called GAMESIT, this e-training system has an added gamification layer. Drawing upon Malone's theory of intrinsically motivating instruction, we choose and design gamification elements (e.g., levels, avatar evolution, and distinct visuals) to create appropriate motivational drivers, namely, challenge, curiosity, and fantasy, for learning tasks. We follow a design science framework to iteratively develop GAMESIT and evaluate its effectiveness. In a laboratory experiment, participants using GAMESIT, when compared to those using the non-gamified e-training system, showed improvement in learning outcomes, measured as learners' knowledge comprehension and task performance, and higher engagement, captured through learners' cognitive effort.