Basic military training lays the foundation for dealing with the special demands and stresses of military service. This initial training period is physically and mentally challenging. Thus, it is ideally suited to identify factors that are linked to wellbeing and long-term operational readiness of soldiers. Objectives of this preventive medicine-oriented study were 1) to identify factors influencing health perception, stress perception, and military performance and 2) to assess the practical relevance of these factors. Questionnaire data collected from 135 male recruits at the start and at the end of their basic military training indicates resilience, mindfulness, and self-efficacy expectations as relevant psychological factors: recruits with a higher level of these three resources report significantly less stress at the end of training. In addition, they also rate their military performance at the end of training higher than other recruits do. Additional exploratory analyses show a positive development of self-efficacy across training that is not present for resilience and mindfulness. Hence, these resources should be strengthened with specific trainings to not only to improve basic military training, but to prepare for the demands and stresses of military service.