Dr. Marcella Marcey has worked within the field of psychology since 1972, when she received her first master's degree. She worked for thirteen years as a school psychologist in Fairfax County, Virginia. In 1988, she returned to school to earn a second master's degree and her Ph.D. in Clinical Psychology from George Mason University. She has since maintained a private practice for over 20 years.

In addition to seeing clients on an individual basis, she also provides couples and family counseling, and group therapy.

She currently leads support groups for loved ones of homicide victims for both the state of Virginia, and Loudoun County, Virginia. Dr. Marcey wrote her dissertation on the long-term effects of experiencing the traumatic death of an individual or loved one, with particular emphasis on loss by homicide and other sudden deaths. She has extensive experience working with the surviving family members of homicide victims.

She often uses trained therapy dogs in her practice, as they serve as important companions and allow distressed clients to feel safe, comfortable and welcome. She maintains a 'dog-friendly' practice and usually brings her dogs to work with her daily.

Outside of her private practice, Dr. Marcey is an adjunct professor at George Mason University, Northern Virginia Community College (NOVA), and Lord Fairfax Community College.