In this study, we employ ‘hidden workers’ as a key concept to integrate the three vulnerable subgroups of aging workers: underemployed, unemployed, and discouraged workers. (1) Background: The challenges faced by underemployed, unemployed, and discouraged workers in the older population are complex. It would be beneficial to visualize the intellectual landscape of these three distinct groups in aging populations to understand which aspects have been highlighted by various disciplines and where gaps exist. (2) Method: Through a scientometric analysis of more than 50 years of research, this study identified the size, scope, and structure of knowledge on hidden workers in an aging population using 2831 articles collected from the Web of Science database in January 2024. (3) Results: Indeed, the multidisciplinary nature of hidden workers goes beyond welfare and labor economics and involves issues such as health, occupational science, behavior change, policy interventions, and circles around the keyword of unemployment. Keyword co-occurrence and co-citation analysis confirm that the spectrum of research on hidden workers is being carried out distinctly within distinct disciplines across the broader aging research horizon. (4) Conclusions: The relatively scattered and uneven intellectual, conceptual, and social landscape of research on hidden workers in aging populations evidently falls short of providing concerted policy recommendations for the population group. This study provides a conceptual understanding of hidden workers in different research clusters and identifies gaps and opportunities for future research.