This dissertation consists of three papers that investigate the working and caregiving roles of middle-to-older adults and their implications for well-being in China. While existing literature predominantly focuses on older adults as care recipients, this research sheds light on the significant number of older individuals who actively participate in the labor market and provide informal caregiving to family members. Studies usually focus on either caregiving or employment while keeping the other in the background, leaving the intersection of work and caregiving responsibilities understudied. I then ask whether and how work-life conflicts, commonly discussed in the context of middle-aged women, are also applicable to the older population and are shaped by gender. Using data from the China Health and Retirement Study, the study investigates work and caregiving patterns among middle-to-older adults and explores the well-being consequences of juggling these roles. Furthermore, the research examines whether gender-based patterns persist in work and caregiving dynamics during this stage of life. The study is conducted in China, a developing country experiencing accelerated population aging, and the boundaries between work and family responsibilities are less distinct compared to developed societies. Early retirement age in the formal sector provides opportunities for older workers to engage in caregiving, while informal sector and agricultural workers may need to continue working until old age due to low pension rates. The culture of filial piety and intergenerational solidarity further encourages older generations to provide financial and caregiving support to their younger family members, leading to the common occurrence of middle-to-older adults taking on both work and caregiving roles. The first paper explores the association between living arrangements and middle-to-older adults’ work prospects, considering gender and work sector differences. The second paper examines the impacts of living arrangements on role transitions, especially the transitions of workers and worker-caregivers given their prevalence, while also considering the moderating effects of gender and residence. The third paper investigates the joint impact of work and informal caregiving on mental well-being, analyzing the differential effects based on intensity, gender, residence, socioeconomic status, and social isolation level. In the context of accelerated aging in developing countries, this dissertation highlights the contributions of middle-to-older adults and emphasizes the need for investment in and design of long-term care services to meet the demands of rapidly aging populations.