This paper elaborates on the teacher change process described in the Interconnected Model of Teacher Professional Growth by providing empirical evidence from a study that investigated the knowledge construction process of three mathematics teachers in Melbourne, Australia. Through a research design that aimed to facilitate teacher reflection regarding their learning processes during the design and teaching of lessons, two mechanisms of teacher learning were identified: consolidation in terms of reinforcement of existing knowledge and beliefs, and realisation of new knowledge and beliefs. This finding prompted a reconceptualisation of the nature of teacher professional growth.