At Baltimore City Hospitals, Dr. Ruby performed his internship and residency. He became the Chief Medical Resident and a fellow at Johns Hopkins Hospitals. His fellowship training in endocrinology was at Harbor UCLA where he was the Chief Resident. Fellowship interest were in diabetes, obesity, and thyroid disease.

He is a charter member and fellow of the American Association of Clinical Endocrinologists and a member of the National Lipid Association, American Diabetes Association and the Endocrine Society. He has been in the South Bay since 1980 practicing Internal Medicine and Endocrinology. Dr. Ruby has served as the medical director on the board of directors for the South Bay Independent Medical Group. He was the chief of staff at South Bay Hospital. Currently serving as director of the medical education at Providence Little Company of Mary. His current clinical research involves early diagnosis and treatment of pre-diabetics and recognition of premature vascular disease.

Dr. Ruby is a published author and serves as a national speaker for osteoporosis. He is a lifelong sports enthusiast, plays paddle tennis and has a great interest in photography. His wife, two sons and two grandchildren remain the primary focus of his busy and productive lifestyle. His last publication was in the international journal The Lancet-Diabetes & Endocrinology in October 2018 called STOP DIABETES.