The impact of indoor air quality (IAQ) on occupant health is undeniable because we spend a majority of our time indoors. This means the design and construction of multi-family rental buildings have potential health impacts for low-income families. The low-income-housing-tax-credit (LIHTC) federal program, administrated by state housing finance agencies, provides a policy system that can improve building quality, potentially influencing occupant health. Recent assessments on LIHTC's criteria showed the effectiveness of this program to advance better-quality housing. However, there is no study on IAQ-related criteria for building design and construction (BDC) of LIHTC buildings. This paper aims to assess the IAQ implementation process, to explore what practices developers utilized and how these practices improved IAQ. Using a qualitative approach, one case study of a rehabilitation project in Washington, DC, is analyzed. A 2014-study showed IAQ improvements in this project after renovation. Semi-structured interviews with the developer of this LIHTC-project revealed that ventilation is the most challenging IAQ strategy for a rehabilitation project. The project utilized integrative design and multi-criteria decision making as the practical tools for IAQ implementation practices. This research offers guidance for building practitioners to improve the green and healthy aspects of affordable housing.