Dr. Preston Cannady Jr. received his medical degree from the University of Alabama School of Medicine in 1969. He completed an internship and residency in internal medicine at the William Beaumont Army Medical Center. He also completed fellowships in infectious disease at the Brooke Army Medical Center and the University of Texas Southwestern Medical School.

Dr. Cannady is certified in internal medicine and infectious disease by the American Board of Internal Medicine.

He previously served as the program director for the Chicago Medical School's internal medicine residency program at Northwestern Medicine McHenry Hospital.