Insurers and employers are increasingly offering lifestyle and weight-loss coaching programs; however, few evaluations have examined their effectiveness. Our objectives were to determine whether level of program engagement was associated with differences in healthcare utilization and weight pre/post coaching. We conducted a retrospective evaluation of enrollees in an insurer-based telephonic health coaching program in Maryland (2013–2014). Our independent variables were program engagement benchmarks (≥3 and ≥6 sessions). Our dependent variables included change in outpatient and emergency department (ED) visits (more visits post program, fewer visits post, or no change pre-post) and associated costs (difference pre-post) using claims data. We calculated mean percent weight change from baseline. We used multivariate-adjusted linear and multinomial logistic regression, as appropriate, to examine the association between outcomes and engagement benchmarks. We included 225 enrollees with mean age 50.7 years, 81.3% women, and mean body mass index of 35.0 kg/m². Most participants focused on weight management(75.6%) and improving general health (57.8%). Few individuals had outpatient or ED visits, and no significant changes in healthcare utilization were associated with program engagement. Among the weight management subgroup (n = 170), mean weight change was −2.1% (SD 5.1). Participants achieved significantly greater weight loss if they met the 6-session engagement benchmark (β −3.5%, p < 0.01). Weight management is a popular focus for health coaching participants, and these programs can achieve modest weight loss. Programs should consider designing and testing strategies that promote engagement, given that weight-loss success was improved if participants completed at least 6 coaching sessions.