This integrative review aims to render a systematic account of the role that teachers' psychological characteristics, such as their motivation and personality, play for critical outcomes in terms of teacher effectiveness, teachers' well-being, retention, and positive interpersonal relations with multiple stakeholders (e.g., students, parents, principals, colleagues). We first summarize and evaluate the available evidence on relations between psychological characteristics and these outcomes derived in existing research syntheses (meta-analyses, systematic reviews). We then discuss implications of the findings regarding the eight identified psychological characteristics--self-efficacy, causal attributions, expectations, personality, enthusiasm, emotional intelligence, emotional labor, and mindfulness--for research and educational practice. In terms of practical recommendations, we focus on teacher selection and the design of future professional development activities as areas that particularly profit from a profound understanding of the relative importance of different psychological teacher characteristics in facilitating adaptive outcomes.