A central aim of research in the psychological and decision sciences is to establish interventions that enhance performance, investigating the efficacy of modern approaches to improve human inference and decision-making. Whereas the decision sciences have established interventions to reduce decision biases by promoting strategies for critical thought and reasoning, methods from psychology have instead focused on enhancing cognition through skill-based training of executive functions. Contemporary research in psychology has engaged these operations through multi-modal interventions designed to enhance cognition and physical health through training of executive functions, mindfulness meditation, and physical fitness. Despite the comparable aims of research in the psychological and decision sciences, the efficacy of multi-modal interventions to enhance decision-making remain to be established. We therefore conducted a comprehensive, 16-week, randomized controlled trial (RCT) to investigate this issue, enrolling 160 healthy adults in one of four interventions: (1) high-intensity cardioresistance fitness training (HICRT); (2) HICRT and cognitive training of core executive functions; (3) HICRT and cognitive training, along with mindfulness meditation training; or (4) active control training. The results of our RCT demonstrate that HICRT training and multi-modal interventions that also incorporate cognitive training and mindfulness meditation have beneficial effects on decision-making competence. The observed pattern of findings motivate the application of modern interventions from psychology and cognitive neuroscience to enhance human judgment and decision-making in complex, real-world environments.