In everyday life and in education, we continuously build and structure our knowledge. Successful knowledge construction is suggested to happen through reactivation of previously learned information during new learning. This reactivation is presumed to lead to integration of old and new memories and strengthen long-term retention. Additionally, congruency with prior knowledge is shown to enhance subsequent memory. However, it is unknown how subjective reactivation and congruency jointly influence learning in an educational context. In two experiments, we investigated this question using an AB-AC inference paradigm where students were asked to first study an AB (word-picture) and then an AC-association (word-description). BC-associations were either congruent or incongruent and were linked by a common, unknown word (A). During AC-learning, participants were instructed to actively reactivate B (the picture) and report their subjective reactivation strength. Participants were first-year university students studying either psychology or family studies and the stimuli consisted of new information from their curricula. We expected that both reactivation and congruency would enhance subsequent associative memory for the inferred BC-association. This was assessed by cueing participants with C (the description) and asking to freely describe the associated picture. Results show a significant enhancement of both B-reactivation and congruency on associative memory scores in both experiments. Additionally, subjective meta-memory measures exhibited the same effect. These outcomes, showing beneficial effects of both reactivation and congruency on memory formation, can be of interest to educational practice, where effectively building knowledge through reactivation is imperative for success.