The study examined how junior residents perceive and build learning alliances with attending physicians during a two-month ED rotation in Japan. They conducted semi-structured interviews with 14 residents and analyzed them using a thematic analysis according to the three components of the alliance: shared goals, agreement on strategies and development of trust. Residents actively shared and modified their learning goals through formal discussions and informal interactions. Despite the differences in the teaching strategies of the attending physicians, they created their own styles through reflection and adaptation. Some faced reduced autonomy due to unilateral instructions or conflicts between patient safety and education. Trust was built gradually based on the attitudes, communication and clinical judgment of the attending physicians, which promoted psychological safety. Despite time constraints, it is possible to build such alliances and the quality of involvement of attending physicians is crucial.