After graduation Howard earned a medical degree from the University of Rochester School of Medicine and then was a student fellow in the department of pathology. He was an intern and resident at the V.A. Hospital and Parkland Memorial Hospital in Dallas, Texas, from 1958 to 1961.
After serving as a research fellow in the department of physiology at Dartmouth, Howard went into private practice in internal medicine and cardiology in Dallas. He was an honorary member and past president of the Texas Heart Association.
Howard died March 30, 2017. He is survived by his wife, Wynona; three children; nine grandchildren; and nine great-grandchildren.