ImportancePhysicians’ knowledge about each other’s quality is central to clinical decision-making, but such information is not well understood and is rarely harnessed to identify exemplars for disseminating best practices or quality improvement. One exception is chief medical resident selection, which is typically based on interpersonal, teaching, and clinical skills.ObjectiveTo compare care for patients of primary care physicians (PCPs) who were former chiefs with care for patients of nonchief PCPs.Design, Setting, and ParticipantsUsing 2010 to 2018 Medicare Fee-For-Service Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey data (response rate, 47.6%), Medicare claims for random 20% samples of fee-for-service beneficiaries, and medical board data from 4 large US states, we compared care for patients of former chief PCPs with care for patients of nonchief PCPs in the same practice using linear regression. Data were analyzed from August 2020 to January 2023.ExposuresReceiving the plurality of primary care office visits from a former chief PCP.Main Outcomes and MeasuresComposite of 12 patient experience items as primary outcome and 4 spending and utilization measures as secondary outcomes.ResultsThe CAHPS samples included 4493 patients with former chief PCPs and 41 278 patients with nonchief PCPs. The 2 groups were similar in age (mean [SD], 73.1 [10.3] years vs 73.2 [10.3] years), sex (56.8% vs 56.8% female), race and ethnicity (1.2% vs 1.0% American Indian or Alaska Native, 1.3% vs 1.9% Asian or Pacific Islander, 4.8% vs. 5.6% Hispanic, 7.3% vs 6.6% non-Hispanic Black, and 81.5% vs. 80.0% non-Hispanic White), and other characteristics. The Medicare claims for random 20% samples included 289 728 patients with former chief PCPs and 2 954 120 patients with nonchief PCPs. Patients of former chief PCPs rated their care experiences significantly better than patients of nonchief PCPs (adjusted difference in composite, 1.6 percentage points; 95% CI, 0.4-2.8; effect size of 0.30 standard deviations (SD) of the physician-level distribution of performance; P = .01), including markedly higher ratings of physician-specific communication and interpersonal skills typically emphasized in chief selection. Differences were large for patients of racial and ethnic minority groups (1.16 SD), dual-eligible patients (0.81 SD), and those with less education (0.44 SD) but did not vary significantly across groups. Differences in spending and utilization were minimal overall.Conclusions and RelevanceIn this study, patients of PCPs who were former chief medical residents reported better care experiences than patients of other PCPs in the same practice, especially for physician-specific items. The study results suggest that the profession possesses information about physician quality, motivating the development and study of strategies for harnessing such information to select and repurpose exemplars for quality improvement.