Dr. Francisco J. Diaz received his medical degree in his native country, Dominican Republic. After receiving his medical degree, Dr. Diaz trained in Anatomic Pathology at Conemaugh Memorial Medical Center in Johnstown, Pennsylvania/Temple University. In 2000, Dr. Diaz accepted a fellowship in forensic pathology with the Office of the Chief Medical Examiner in Philadelphia, Pennsylvania in affiliation with Hahnemann University (now Drexel University).

After completing the forensic pathology fellowship, Dr. Diaz joined the Office of the Chief Medical Examiner in Wayne County, Michigan as an Assistant Medical Examiner. In January 2012, in affiliation with the Wayne County Medical Examiner's Office, Dr. Diaz was appointed to the University of Michigan faculty, Department of Pathology as Assistant Professor. Dr. Diaz was a Medical Examiner in Michigan for 16 years.

Dr. Diaz has performed more than 8500 autopsies during his career and testified hundreds of times in circuit, district, and federal courts. He has also provided numerous civil depositions. Dr. Diaz is the co-author of "Spitz and Fisher Medicolegal Investigation of Death on his 5th edition.

Dr. Diaz has also co-authored 35 peer-reviewed articles, abstracts, and presentations and has been invited on numerous occasions to speak at regional, national, and international conferences. He is board certified in Anatomic Pathology as well as Forensic Pathology. He is a fellow of the College of American Pathologists (CAP) and the National Association of Medical Examiners (NAME), and the American Society for Clinical Pathology (ASCP).

He is a member of the board of directors and the government affairs committee's chair for NAME.  After joining DC OCME, Dr. Diaz was appointed to the faculty of George Washington University School of Medicine and Health Sciences and holds Assistant Professor's rank.

Dr. Diaz joined the Department of Forensic Sciences as the Interim Director in May 2023.

Dr. Diaz enjoys reading and traveling when he is away from the office.