Leader–follower relationships are a cornerstone of leadership research. Considering recent developments that point to emotions as key determinants of dyadic relationships, we shift the focus of this literature to the episodic interplay of leader emotional expressions and follower emotional reactions for the emergence of high‐quality interactions. Specifically, we develop an emotional entrainment perspective stating that the trajectory of leader emotional expressions and corresponding follower emotional reactions over the course of a day gives rise to follower perceptions of their interaction quality with their leader. We glean additional insights by examining follower attachment styles as a moderator. Results of an experience sampling study (Nemployees = 72, Ndays = 479) demonstrate that emotional entrainment of high‐activated emotions (joy and fear) predicts end‐of‐day interaction quality contingent on followers' (avoidant and anxious) attachment styles. Future avenues for research on the emergence of high‐quality leader–follower relationships are discussed.