To what extent has the constructivist teaching-learning concept been received by teachers, and how is it reflected in their professional knowledge and teaching actions? This work contributes theoretically, methodologically, and content-wise to current questions regarding the professional competence of teachers. The analysis of the awareness of action knowledge from philosophical and psychological perspectives, along with the identification of various elements of professional knowledge, provides a comprehensive foundation for capturing teaching-related cognitions using multiple methods. The empirical investigation examines teaching quality from multiple perspectives by capturing teacher cognitions through various methods and relating them to indicators of video-based actions of the teachers as well as to students' self-perceptions.