Purpose <p>Vaccination remains the most effective global countermeasure against the COVID-19 pandemic. Exploring the underlying determinants of both vaccine uptake and hesitancy, particularly across distinct age cohorts, is essential for optimizing preparedness for future pandemics.</p> Methods <p>This study examines age-specific patterns and determinants of COVID-19 vaccination and vaccine hesitancy in China, utilizing a nationally representative sample of 7,074 adults drawn from the 2021 Chinese General Social Survey.</p> Results <p>By the end of 2021, only 53.84% of adults aged 60 and older had received at least one vaccine dose, significantly lower than the 83.66% rate among the labor force population (aged 18–59). Key determinants of vaccination uptake included female gender (OR = 1.18, 95% CI: 1.05–1.33), rural residence (OR = 1.20, 95% CI: 1.05–1.38), lower income (OR = 1.55, 95% CI: 1.33–1.80), marriage, employment, greater social and internet engagement, and better self-rated health. Notably, gender and income were significantly associated with vaccination only in the labor force, whereas rural residence and social engagement were significant only among older adults.</p> Conclusions <p>In contrast to international evidence, Chinese individuals with socio-demographic characteristics often linked to vulnerability (e.g., female, rural, low-income) showed higher vaccine acceptance, while favorable health and employment statuses facilitated uptake. Concerns regarding health risks and contraindications were the primary drivers of hesitancy, particularly among older adults. These results provide valuable insights for designing age-tailored public health strategies to enhance vaccination coverage during future pandemics.</p>