Beginning primary teachers’ knowledge and beliefs were assessed at the end of teacher education and 4 years later. In addition, they reported about their school context and job satisfaction and took a video-based assessment on their perception, interpretation, and decision-making skills. Research questions were (1) whether we have to deal with a “reality shock” in that beginning teachers’ beliefs change to more traditional ones or whether their knowledge decreases, (2) whether the school context in terms of appraisal and a climate of trust influences the knowledge and belief development, and (3) to what extent the beginning teachers’ knowledge and beliefs predict their perception, interpretation, and decision-making skills. Data from 231 German primary teachers in their third year in the profession neither revealed changes of beliefs towards traditional ones nor a substantial loss in knowledge. In contrast, general pedagogical knowledge (GPK) grew significantly and beliefs on the nature of mathematics were more dynamic 3 years after teacher education. Thus, drawbacks are a rare phenomenon in our sample. Those teachers who had perceived a stronger climate of trust revealed higher content knowledge, pedagogical content knowledge and GPK as well as more dynamic beliefs. These teachers also revealed significantly stronger performance-related skills.