This study contributed to knowledge of indoor environmental quality (IEQ) in assisted living facilities (ALFs) by examining staff satisfaction with the work environment, perceived productivity, and attitudes toward environmental sustainability in the workplace. An ALF Staff IEQ Survey was administered to staff (N = 94) at 12 ALFs, which were newly constructed or renovated within the last 10 years. Staff who participated in the survey were divided into three age groups (young, middle-aged, and older) and two categories of responsibilities (medical and nonmedical). The questionnaire was designed to incorporate the Occupant IEQ Survey (Center for the Built Environment, 2013) and the Leadership in Energy and Environmental Design (LEED) rating criteria. It comprised six IEQ categories: space layout, thermal comfort, air quality, lighting and views, acoustic quality, and facility cleanliness and maintenance. Spearman's rank-order correlation coefficient, Kruskal–Wallis, and Mann–Whitney U tests were used for data analysis. Results identified 23 IEQ factors in all IEQ categories that significantly contributed to staff productivity. Six IEQ factors in four IEQ categories (space layout, thermal comfort, lighting, and facility cleanliness) were significantly related to staff environmental attitudes. In addition, 12 IEQ factors within five IEQ categories (except lighting quality) were found to have notable differences by age discrepancy, whereas five IEQ factors of air quality and facility cleanliness were significantly different for medical and nonmedical staff. The findings of this study provide designers with prioritized demands and preferences for decision making in terms of improving the work environment for the health and well-being of ALF staff. By incorporating the paradigms of evidence-based design (EBD), human-centered design (HCD), and sustainable design (SD), this study proposes a new triadic framework to transition from the current resident-centered model in elder care to a multistakeholder-focused model.