The aim was to evaluate the 6-month and 1-year effects of a person-centered group-based health-promoting intervention on independence in daily activities and self-rated health. The study was an RCT with follow-ups at 6 months and 1 year. A total of 131 independent living people (70+) who have migrated to Sweden from Finland or Western Balkan region were included. Participants were independent in activities of daily living and cognitively intact. They were randomized to an intervention group receiving four weekly group-meetings and a follow-up home visit, or a control group (no intervention). An overall chi-squared test was performed and the odds ratio calculated. A high proportion of the participants maintained independence in activities of daily living and improved or maintained self-rated health. However, no significant differences were found between the groups. The result indicates that the intervention was offered too early in the aging process to be able to detect effects. Methodological challenges were met during both the recruitment and implementation phases. In response to lessons learned, a multicenter design is recommended for future research in order to strengthen the findings. Furthermore, this study has contributed with experiences on both opportunities and challenges in terms of research with and about older people aging in the context of migration, as is discussed.