Dr. Kosh was born and raised in Chicago, Illinois, where he attended Northwestern University, majoring in biology and anthropology. He continued at Northwestern University Medical School, attending on a Navy scholarship, and graduated in 1975. While at Northwestern he was selected for membership to Alpha Omega Alpha, a medical honorary society which admits only the top 10% of each medical school class. Initially board certified in Family Practice in 1976, he continues to score in the 99th percentile on the re-certification exam taken every six years.
Following medical school he was a resident in Family Practice at the Naval Regional Medical Center in Jacksonville, Florida. In his last year of residency, he was Chief Resident, supervising 27 residents in Family Practice. Obstetrics was an integral part of his residency and by the time he left Jacksonville he had delivered over 600 babies.
Following residency, Dr. Kosh was assigned to the Naval Hospital in Long Beach, California. Upon arrival, he was sent on temporary duty to Adak in the Aleutian Island chain. During his stay in the Aleutians, Dr. Kosh was the only physician delivering babies in a radius of two thousand miles. After this temporary assignment, he returned to Long Beach and became Director of the Family Practice Department with a staff of twelve physicians.
In 1983, Dr. Kosh resigned his regular commission and took his family overseas as an embassy physician for the Department of State, serving for three years in Kinshasa, Zaire (now Democratic Republic of Congo) and four years in New Delhi, India. His duties overseas included providing family medical care for American government personnel and dependents and serving as a 'circuit rider' for embassies throughout the region.
Wanting to continue 'hands-on' patient care, Dr. Kosh declined an administrative post in Washington, D.C. and returned to California as a private physician. He assumed the practice of retiring doctor Peter Pavitt in 1990.
Married 33 years with four grown children, he lives ten minutes from Methodist Hospital in nearby Elk Grove.