Dennis M. Robertson was born in South St. Paul, Minn., and grew up in a musical family on the Mississippi River. He completed his undergraduate and graduate training at the University of Minnesota, where he received a B.A., B.S. and M.D.
Following an internship at San Bernardino County Hospital in California, he worked for two years on Indian reservations under the umbrella of the United States Public Health Service. He later completed a residency in ophthalmology at Mayo Clinic and pursued postgraduate fellowship training in vitreoretinal disorders at the Bascom Palmer Eye Institute in Miami. He returned to Mayo Clinic in Rochester, Minn., in 1967.
His studies included a sabbatical during 1987 and 1988 at Moorfields and St. Bartholomew's hospitals in London. His scientific interests have been chiefly in disorders of the retina and vitreous and ocular oncology. In 1999, he became the recipient of the Whitney and Betty MacMillan Professorship.
He retired from full time clinical practice in July 2004. In August 2005, he returned to work part-time at the Mayo Clinic until retiring again in December 2007.