Dr. Gallagher otained her Ph.D. in clinical psychology from the University of Southern Mississippi in 2001. She completed a predoctoral internship in pediatric and clinical child psychology at Children's National Medical Center in Washington, DC, and a postdoctoral fellowship in pediatric psychology at the Children's Hospital at the Cleveland Clinic. She is currently licensed as a clinical psychologist in the state of New Hampshire.

Dr. Gallagher has been trained in clinical child and pediatric psychology, and provides evaluation and treatment to children, adolescents, and their families. She has worked in a variety of inpatient and outpatient settings, and treats children with anxiety, mood, and behavioral difficulties, as well as those adjusting to chronic and acute illness. She specializes in pain management and the treatment of anxiety disorders in childhood.