The pediatric adaptation of the Collaborative Health Outcomes Information Registry (Peds-CHOIR) is a free, open-source, flexible learning health care system (LHS) that meets the call by the Institute of Medicine for the development of national registries to guide research and precision pain medicine. This report is a technical account of the first application of Peds-CHOIR with 3 aims: (1) to describe the design and implementation process of the LHS; (2) to highlight how the clinical system concurrently cultivates a research platform rich in breadth (eg, clinic characteristics) and depth (eg, unique patient- and caregiver-reporting patterns); and (3) to demonstrate the utility of capturing patient-caregiver dyad data in real time, with dynamic outcomes tracking that informs clinical decisions and delivery of treatments. Technical, financial, and systems-based considerations of Peds-CHOIR are discussed. Cross-sectional retrospective data from patients with chronic pain (N = 352; range, 8-17 years; mean, 13.9 years) and their caregivers are reported, including National Institutes of Health Patient-Reported Outcomes Measurement Information System (PROMIS) domains (mobility, pain interference, fatigue, peer relations, anxiety, and depression) and the Pain Catastrophizing Scale. Consistent with the literature, analyses of initial visits revealed impairments across physical, psychological, and social domains. Patients and caregivers evidenced agreement in observable variables (mobility); however, caregivers consistently endorsed greater impairment regarding internal experiences (pain interference, fatigue, peer relations, anxiety, and depression) than patients' self-report. A platform like Peds-CHOIR highlights predictors of chronic pain outcomes on a group level and facilitates individually tailored treatment(s). Challenges of implementation and future directions are discussed.