<p>Despite the prevalence of chronic pain among patients presenting to primary care, access to evidence-based psychological intervention remains limited. Mobile health (mHealth) interventions offer scalable alternatives, but little is known about how specific engagement behaviors relate to clinical outcomes. This secondary analysis explored the value of distinct engagement components as predictors of pain outcomes&#xa0;across two pilot trials of an eight-week mHealth program for adults (<i>N</i> = 39) with co-occurring chronic pain and hazardous drinking. Engagement indices included skills library access, skill reviews, homework surveys completed, videos opened and completed, and frequency of instant messaging coaching sessions. Pain outcomes were assessed with the Pain, Enjoyment of Life, and General Activity (PEG) scale at baseline and 12–16&#xa0;weeks post-baseline. Analyses included partial correlations controlling for trial and descriptive analyses from median split cross-tabulations to examine associations between engagement and achievement of clinical improvement in pain. Higher engagement with skills reviews, completion of homework surveys, and number of videos completed emerged as indices most highly associated with a greater likelihood of achieving ≥ 30% pain reduction. Frequency of coaching sessions, however, did not appear to be linked with outcomes. Findings suggest that certain engagement behaviors––particularly videos completed––may be predictive of clinical benefit, underscoring the potential importance of depth and quality of engagement. These results highlight specific engagement indices that may be important to track and potentially enhance to improve clinical outcomes for mHealth interventions for chronic pain.</p>