This study aimed to examine the nursing management behaviors of nurse managers at Hospital A and to identify challenges in developing nurse managers capable of implementing nursing management behaviors based on the competency model. Individual interviews were conducted twice with nine nurse managers. Newly appointed nurse managers demonstrated competencies related to supporting others, such as “self-improvement and learning ability”. The competencies requiring further development included “interpersonal influence”, which also relates to supporting others. Among nurse managers with more than 4 years of experience, both the competencies they exhibited and those requiring further improvement included “commitment to the organization”, with references to contributing to the overall benefit of the hospital. Newly appointed nurse managers need support in reflecting on their nursing management behaviors by observing and learning from others. Meanwhile, nurse managers with over 4 years of experience require assistance in collaborating with other departments to contribute to the hospital as a whole.