Dr. Grieb is board-certified in internal medicine, hematology and medical oncology. He graduated from the University of Nebraska Medical Center and completed his residency in internal medicine at the Mayo Clinic in Rochester, Minnesota, followed by a three-year fellowship in medical oncology and hematology also at the Mayo Clinic. His undergrad is from the University of Nebraska-Lincoln. He also was a student-athlete while at UNL competing in cross country and track and field. 

Dr. Grieb is a member of the American Society of Clinical Oncology, the American Society of Hematology, the American College of Physicians, the Nebraska Medical Association, and the Lancaster County Medical Society and is an affiliate member of the UNMC Eppley Cancer Center. He is also an Investigator with the Alliance for Clinical Trials in Oncology and the ECOG-ACRIN Cancer Research Group. He is originally from York, Nebraska, and is married with three children.