Background“New nurses” are those with less than a year of work experience at a hospital. To address the challenges of new nurses caused by their limited experience, the Mentoring New Nurses for Transition and Empowerment Program (MNTEP) was designed based on the Stress-Appraisal-Coping Model of Lazarus and Folkman. ObjectivesThis study aimed to explore the impact of the MNTEP, in which clinical nurse educators teach stress-coping strategies, on the clinical transition of new nurses in South Korea. DesignThis study used a mixed-methods design with a pretest-posttest non-equivalent comparison group and focus group interviews (FGIs). SettingsThe research was conducted at a hospital in South Korea. ParticipantsThe intervention and comparison groups comprised 30 and 28 new nurses, respectively. Also, 12 MNTEP participants were subjected to three separate FGIs. MethodsTo comprehensively assess the program's effects, quantitative data were collected through self-report surveys, while qualitative data were obtained from March 2022 to March 2023 using semi-structured interviews that allowed for open-ended responses. ResultsThere were significant differences in mean self-efficacy scores (t = 2.45, p = 0.017) and perceived social support from clinical nurse educators (F = 4.51, p = 0.038) between the intervention and comparison groups. Additionally, significant changes were observed in the field adaptation pre-test and post-test scores within the intervention group (t = −3.12, p = 0.004). However, there was no statistically significant difference between the groups in terms of active and passive coping strategies. FGIs yielded two main themes: (1) gaining positive energy through empowerment and solidarity; and (2) clinical nurse educators sharing strategies for improved role adaptation and capacity building. ConclusionsMNTEP led by clinical nurse educators positively influenced new nurses' self-efficacy and facilitated their transition to clinical settings. These findings underscore the importance of mentorship programs and clinical nurse educators.