In this article, the authors captured housing events and health care service utilization during 2 years prior to the first program eligibility date (baseline) and 2 years post-baseline. They performed sequence analysis to measure housing stability and compared housing stability and preventable ED visits and hospitalizations between program participants (treatment group) and eligible applicants not placed in the program (comparison group) via marginal structural modeling. Supportive housing placement was associated with improved housing stability and reduced preventable health care visits among homeless families.