Purpose To investigate the changes in pain, physical and activities of daily living (ADL) functioning in vulnerable older adults with chronic pain after proactive primary care intervention. Methods This study was embedded in a prospective, pragmatic, matched-control multicenter trial at 19 primary care practices in Sweden, with proactive medical and social care (Intervention Group, IG, n = 134) in comparison with usual care (Control Group, CG, n = 121). Patients with chronic pain, defined as pain experienced longer than 3 months, were included in this subgroup analysis. Data on pain aspects, physical and ADL functioning were collected in the questionnaires at baseline, one- and two-year follow-up (FU-1 and FU-2). Data on prescribed pain medications was collected by local health authorities. Results Mean age was 83.0 +/- 4.7 years with almost equal representation of both genders. From baseline until FU-2, there were no significant within-group or between-group changes in pain intensity. Small adjustments of pain medication prescriptions were made in both groups. Compared to FU-1, the functional changes were more measurable at FU-2 as fewer participants had impaired physical functioning in IG (48.4%) in comparison to CG (62.6%, p = 0.027, Effect Size phi = 0.14). Higher scores of ADL-staircase (more dependent) were found in both groups (p < 0.01, Effect Size r = 0.24 in CG and r = 0.16 in IG). Conclusion Vulnerable older adults with chronic pain seemed to remain physical and ADL functioning after proactive primary care intervention, but they may need tailored strategies of pain management to improve therapeutic effects.