This study aims to examine the functional status of Korean centenarians, who have crossed the relatively rare but increasingly common life transition of living for a century. As functional health is one of the essential components of healthy aging, our primary objective is to identify the correlates of two aspects of functioning, activities of daily living (ADL) and instrumental activities of daily living (IADL). Using a census survey conducted by the Korean National Statistical Office (KNSO) in 2005, we documented ADL and IADL limitations and analyzed their relationship to sociodemographic factors, health behaviors, social connectedness, and presence of diseases. The study participants were 796 adults aged 100 years or older. The mean age was 101.5 ± 1.8, and females were 89.9% of the sample. Both ADL and IADL dependences were more common among females, those who did less physical activity, those who had more diseases, and those who did not participate in social activities. Intervention programs designed to address life-stage issues such as focusing on initiating healthy behaviors from youth, managing chronic diseases in mid-life, and fostering social participation in later life are recommended ways to improve functional independence and promote healthy aging among current and future generations of Korean centenarians.