Dr. Massi began her career as a paraprofessional in 1981 and transitioned to seeing clients as a professional in 1996. She has worked as an arbitrator, paraprofessional domestic violence counselor, and student advisor, as well as a professor at Stanford University and Washington State University. She has directed programs dedicated to early childhood therapy, and has worked in inpatient settings that include prisons, adult mental health living programs, and nursing homes.

In her outpatient work, Dr. Massi has worked with patients from birth through geriatric stages, workers compensation patients, and survivors of major disasters. Additionally, she has volunteered with the International Critical Incident Stress Foundation to address major disasters and has served an expert for the California Board of Psychology as a writer for the state licensing exam. Dr Massi has also created and produced her own podcast CogKnitive (2008-20017) focusing on psychology and craft work. She is interested in the relationship between craft, narrative, and cognitive psychology.