The current cross-sectional study aimed to investigate social connection and lifestyle factors associated with happiness in urban older adults in mainland China. A total of 709 community-dwelling older adults aged 60 to 99 years completed a comprehensive survey covering demographics, happiness, cognition, lifestyle, sleep, nutrition, and social connections. Samples were divided by age into two groups for analysis: young-old (aged 60 to 69 years) and old-old (aged 70 to 99 years). Social connection factors, including relationships with friends and spouse and use of social media applications, were important predictors for happiness in people in their 60s. Lifestyle factors, including nutritional status and extent of physical activity, were associated with happiness in old-old adults. Sleep quality predicted happiness for both age groups. Living with children and happiness were not significant for either age group. Results suggest that social connection and lifestyle are important factors in promoting happy and healthy successful aging in urban older adults in China. [Research in Gerontological Nursing, 16(3), 147-160.].