The study aimed to examine the relationship among professional growth-need strength, care-task characteristics, critical thinking, and holistic nursing competencies after a care-task design and clinical reasoning program intervention in nursing students. This study used a longitudinal study design. The study was conducted from August 12, 2019 to July 30, 2020. Participants were thirdyear nursing students of a medical university. Data were collected by questionnaires at three time points. Structural equation modeling was used to examine the relationship among all measures variables. A total of 91 students participated in the study. The results show that growth-need strength had a significant positive effect on caretask characteristic and critical thinking and a nonsignificant effect on holistic nursing competencies. Care-task characteristics, however, had a significant positive effect on critical thinking, resulting in improvement in holistic nursing competencies. It is worth noting that the moderating effect of growth-need strength on care-task characteristics and nursing competence relationships could not be established. Our findings suggest the importance of improving students' perceived care-task characteristics through an objective structured clinical examination and, at the same time, promoting students' critical thinking and improving their professional abilities.