矢口 大雄

<jats:title>Abstract</jats:title><jats:p>We identified the mastery processes of experienced psychotherapists by drawing their life histories, which indicated principles for guiding the development of young psychotherapists. Participants were psychotherapists with over 30 years of experience (<jats:italic>N</jats:italic> = 7, six men and one woman, mean age = 71.86 years). The data were analyzed using the trajectory equifinality model (TEM). The results indicated that a psychotherapist might continue to practice even while experiencing conflicts and might eventually integrate and establish their unique therapeutic approach into their work. Essential factors in facilitating the motivation to be a psychotherapist include: hope; good friends, coworkers, and supervisors; experience with many cases; learning from a global perspective; and interest in human beings. Moreover, after the mid‐career, adverse events in participants' private lives had positive effects on their development as experts. It was concluded that the development of a psychotherapist is a process of growth as a person. This study indicated factors necessary to continue as a psychotherapist while facing conflicts, which is considered useful for educating future Japanese psychotherapists.</jats:p>