This study presents a model inspired from a grounded theory methodology based on the successful performance of socially assistive robots in aged-care facilities. Conducting 17 in-depth interviews with nurses and scientists who worked with these robots, we investigated how social robot engagement can lead to the quality of life for aged people. The qualitative findings show 4 categories including socially assistive robots, robot mediation, service enablement and aged-care service innovation. The findings support modelling and implementing aged-care service innovation by social assistive robots.