She has an extensive critical care and administrative nursing background. Lenihan served as a registered nurse in the U.S. Army for thirty years, where she developed an expertise in emergency preparedness and response. She retired as a lieutenant colonel. Lenihan earned her master's degree in nursing and her nursing practitioner certificate at UCSF. She is a member of numerous professional organizations, including the Marine's Memorial Association and American Association of Nurse Practitioners. She has served on the Hospital Council of San Francisco for Emergency Preparedness and the Metropolitan Hospital Task Force City and County of San Francisco. Lenihan is an associate clinical professor at the UCSF School of Nursing. Clinics