Aim: To investigate how NGNs perceived and applied an intervention for preventing stress-related ill health embedded in a transition-to-practice programme when entering their professional life. Design: A qualitative exploratory descriptive design was selected for this study to gain insights and perspectives on the adoption and utilization of the intervention. Methods: In this qualitative methodology process evaluation, semi-structured and audio-recorded interviews were conducted with a sample of 49 nurses. Data were collected between December 2016 and July 2017, and were sorted in NVivo 12 Plus, followed by thematic analysis. Results: The analysis resulted in three change processes stimulated by the intervention: (a) Building acceptance of being new; (b) Gaining insight into professional development and health and (c) Practical steps for skills development, healthy habits and better-organized work. In addition to the three themes, barriers that hindered the progression of the processes were also described. Each process influenced the development of the others by stimulating a deeper understanding, motivation to change and courage to act. Several barriers were identified, including the use of cognitively demanding intervention tools, fatigue, high work demands, inconvenient work hours and a hostile social climate on the ward. Conclusion: This process evaluation showed that newly graduated nurses used knowledge from the intervention and adopted new behaviours largely in accordance with how the intervention was intended to work. Impact: When entering a new profession, it is crucial to receive a well-thought-out, structured and targeted introduction to the new professional role, tasks and work group. Nurses stated that the intervention increased their understanding of the role as new nurses and their insight into how to develop skills that promoted better functioning and recovery. The intervention also stimulated the development of new health behaviour and some new learning strategies. © 2023 The Authors. Journal of Advanced Nursing published by John Wiley & Sons Ltd.