Tobacco use is exceedingly high among those who are homeless or at risk of homelessness but not commonly addressed by clinicians. Taking Texas Tobacco Free (TTTF) is a tobacco control program that addresses known clinician barriers to intervention (e.g., low training receipt, limited resources). Here, we examine the process and outcomes of TTTF’s adaptation within four agencies that provide housing or other services to individuals who are homeless or vulnerably housed. Pre- and post-implementation data were collected from clinicians (N = 68) to assess changes in training receipt, knowledge, and intervention behaviors, relative to program goals. Results indicated significant gains in clinicians’ receipt of training in 9 (of 9) target areas (p’s ≤ 0.0042) and a 53% knowledge gain (p < 0.0001). From pre- to post-implementation, there were mean increases in the use of the 5As (ask, advise, assess, assist, and arrange) and other evidence-based interventions for tobacco cessation, with significant gains seen in assisting residents/clients to quit, arranging follow-ups, and providing or referring for non-nicotine medications (p’s ≤ 0.0491). All program goals, except gains related to advising smokers to quit and the use of specific interventions (behavioral counseling), were met. Overall, TTTF improved clinicians’ capacity to address tobacco use among homeless and vulnerably housed individuals and can serve as a model for tobacco control efforts in similar agencies.