Dr Greenall is a Senior Lecturer in Forensic Psychology. He is also a Senior Forensic Psychologist, working within an NHS Forensic Mental Health Service. He has worked in secure hospitals and prisons, held academic posts at several universities in the northwest of England, and is presently training to become an EMDR practitioner.

Dr Greenall has worked with men with histories of sexual violence and has researched and published in this area. He has a special interest in sexual offending by strangers.