Healthier XX is a national primary care reform introduced in 2023 to strengthen preventive care through patient enrolment, continuity, and personalised care with a regular primary care provider. Evidence on its early impact on preventive service uptake remains limited.To evaluate whether enrolment in Healthier XX is associated with changes in preventive care uptake following COVID-19–related disruptions.We conducted a retrospective cohort study using routinely collected electronic medical records from a major public primary care clinics cluster. The study included 395,156 patients aged 40 years and above with longitudinal engagement between January 2018 and September 2024. Preventive services examined were cervical cancer screening, cardiovascular risk screening, influenza vaccination, and pneumococcal vaccination. Quarterly uptake rates were analysed across four periods: pre-COVID-19, COVID-19, post-COVID-19 recovery, and post-Healthier XX implementation. Segmented time-series regression was used to evaluate changes in trends associated with programme implementation. Subgroup analyses compared patients with prior preventive care utilisation to non-utilisers.Enrolment was more likely among older adults, women, married individuals, and patients with chronic conditions, and less likely among ethnic minority groups, smokers, and residents of lower-income housing. Cervical cancer screening declined during COVID-19 and partially recovered thereafter, with significant post–Healthier XX acceleration among enrolees, while uptake among non-enrolees declined. Cardiovascular risk screening showed high baseline uptake with gradual deceleration and minimal post–Healthier XX acceleration, consistent with a ceiling effect. Influenza and pneumococcal vaccination uptake increased among enrolees but stagnated or declined among non-enrolees. Among prior utilisers, cervical cancer screening recovered stronger among enrolees.  Cardiovascular risk screening in non-enrolees experienced a sustained decline post COVID-19. Among prior non-utilisers, cervical cancer screening improved gradually with greater gains after enrolment, while cardiovascular risk screening increased modestly, with declining trends among non-enrolees.Patient enrolment within a structured primary care reform was associated with improved recovery and divergence in preventive care uptake after the pandemic. However, benefits varied across services and reflected persistent sociodemographic inequities.Healthier XX enrolment was associated with improved recovery of selected preventive services in public primary care post pandemic. Complementary strategies targeting under-represented groups are needed to maximise equitable population-level impact.