Brennan is a Licensed Professional Counselor (LPC) and the Clinical Supervisor/Quality Assurance Specialist of Behavioral Health at the Mazzoni Center.  He received his Master of Education in Counseling Psychology from Temple University.

Prior to joining the Mazzoni Center, Brennan worked as Clinical Supervisor for several community mental health agencies that provided Outpatient Services and Behavioral Health Rehabilitation Services (BHRS) in the city of Philadelphia. Before his time spent working in an administrative capacity, he worked as an outpatient therapist in various settings across Philadelphia working with adults, adolescents, children, couples, families, and groups struggling with mental health and substance abuse issues.