Dr. Halligan was born and raised in Columbia, Maryland. She attended the University of Maryland College Park, where she earned a bachelor’s degree in Physiology and Neurobiology with a minor in Spanish. During her college years, she began volunteering with the Prince George’s County Fire Department, dedicating seven years to service while in college and medical school, including two years living at the firehouse in exchange for free lodging.

In 2000, Dr. Halligan started medical school at the University of Maryland Baltimore, followed by her Emergency Medicine residency at Orlando Regional Medical Center. Upon completing her residency in 2007, she relocated to the Atlanta area to be closer to her parents and two younger brothers, who had moved there during her college years.

She initially worked at Dekalb Medical Center for a year, then spent seven years at North Fulton Hospital in Roswell before joining Georgia Emergency Department Services.