The purpose of this research was to consider the influence of the knowledge and practical experience of clinical psychology on perspectives regarding the provision of developmental support to infants. Subjects were 37 university students majoring in psychology, 20 graduate students from a clinical psychologist training course, and 12 clinical psychologists with practice experience of providing developmental support for infants. Findings revealed that an inclination to identify the developmental meaning of inappropriate infant behavior was acquired through the knowledge and practical experience of clinical psychology, and that the knowledge led to a deeper understanding of developmentally appropriate infant behavior. With reference to interventions for infants, the clinical psychologists focused on both, the reduction of inappropriate behaviors and the increase of appropriate behaviors. For interventions for mothers, the knowledge of clinical psychology led to the approach of collecting information from the mother, while the practical experience led to sharing an understanding of the infant's behavior with the mother. For recognition of the appropriate efforts of mothers, clinical psychologists tended to direct attention to the involvement of the mother to promote interactions with the infant.