Background The Serious Illness Care Program (SICP) is a model developed for structured communication, identifying patients, and training physicians to use a structured guide for conversations with patients and family members. However, there is a lack of knowledge regarding the sustainable implementation of this conversation model. Therefore, the aim of this study was to identify barriers and enablers during the implementation of the SICP in hospital settings. Methods The SICP was implemented at 20 units in two hospitals in Sweden. During the implementation process, seven individual interviews and two group interviews were conducted with seven facilitators (five physicians, one behavioral therapist, and one administrator). Data were analyzed using qualitative content analysis, first inductively, and then deductively using the organizational readiness for change as a theoretical framework. Result The analysis resulted in three factors acting as enablers and eight factors acting as enablers and/or barriers during the implementation of the SICP. The three factors considered as enablers were preliminaries, identifying patients, and facilitator's role. The eight factors considered as enablers and/or barriers were broad implementation, leadership, time, confidence, building foundation, motivation to work change, motivation for training in serious illness conversations, and attitudes. Conclusion This study indicates limited readiness to implement the SICP in hospital settings due to considerable variation in organizational contextual factors, change efficacy, and change commitment. The identified enablers and barriers for implementation of the SICP could guide and support future implementations to be sustainable over time.