Dr. Marshall joined The Baton Rouge Clinic in 1999, coming to Louisiana from New York. He received his M.D. at St. Louis University in St. Louis, Missouri. He completed an internship, a residency, and a fellowship in Rheumatology were all completed at the State University of New York at Stony Brook. Dr. Marshall served in the U.S. Army through 1972. He is a recipient of the Bronze Star and Distinguished Flying Cross. Dr. Marshall is also board-certified in both Internal Medicine and Rheumatology through the American Board of Internal Medicine.