Mary Jane Markell was a Founding Member of Sandplay Therapists of America and a Teaching Member of the International Society of Sandplay Therapists; she served on the Executive Board of ISST for four years. She studied for a number of years with Dora Kalff, both in the United States and in Switzerland. She worked for many years with children and was a founding director of a day treatment program and mental health clinic for children and their families in California.