BACKGROUND: Rapid antiretroviral therapy (ART) initiation, in which people living with HIV start ART within days of diagnosis, is a key component of the US Ending the HIV Epidemic initiative. SETTING: The Memphis Metropolitan Statistical Area ranked fourth in the United States for the highest HIV incidence per 100,000 population in 2018. Rapid ART programs are limited in the Memphis Metropolitan Statistical Area, and our objective was to identify local implementation barriers. METHODS: We conducted participatory process mapping and in-depth interviews to detail steps between HIV testing at the municipal health department's Sexually Transmitted Infections Clinic and ART prescription from a nearby high-volume Ryan White-funded HIV Clinic. RESULTS: Process mapping identified 4 modifiable, rate-limiting rapid ART barriers: (1) requiring laboratory-based confirmatory HIV results, (2) eligibility documentation requirements for Ryan White-funded services, (3) insufficient HIV Clinic medical provider availability, and (4) variability in ART initiation timing among HIV Clinic providers. Staff at both sites highlighted suboptimal communication and sense of shared management between facilities, limited resources to address important social determinants of health, and lack of Medicaid expansion in Tennessee as key barriers. In-depth interview themes negatively affecting rapid ART initiation included clinic burden; provider knowledge, attitudes, and beliefs; and client psychosocial needs. CONCLUSIONS: Our preimplementation work identified modifiable and systemic barriers to systems flow and patient-level outcomes. This work will inform the design and implementation of a locally relevant rapid ART program in Memphis, a community disproportionately affected by the HIV epidemic.