This study investigates how implicit and explicit learning and knowledge are associated, by focusing on the salience of target form–meaning connections. The participants were engaged in incidental learning of artificial determiner systems that included grammatical rules of [± plural] (a taught rule), [± actor] (a more salient hidden rule), and [± animate] (a less salient hidden rule). They completed immediate and delayed post-tests by means of a two-alternative forced-choice task with subjective judgments of source attributions. Awareness during the learning phase was identified through analysis of thinking aloud protocols. The results did not support a one-to-one relation between either explicit learning and conscious knowledge, or implicit learning and unconscious knowledge; rather, they indicated that implicit and explicit learning are intricately linked to conscious and unconscious knowledge mediated by the salience of form–meaning connections in target items. This result also suggests the possibility of the later emergence of knowledge without any conscious awareness of it.