Dr. Rein grew up on a farm near Lanesboro, Minnesota where they raised Registered Angus cattle, hogs, and horses. He received his undergraduate degree in Animal Science from South Dakota State University before graduating from the University of Minnesota College of Veterinary Medicine in the spring of 2001. Dr. Rein practiced in Cashton, WI for 4 1/2 years before joining the Harmony clinic in 2006.​
Dr. Rein specializes in large animal medicine and surgery with an emphasis in dairy and beef production. A large part of his practice includes whole herd production systems, including reproduction, milk quality, biosecurity, young stock rearing, building and ventilation design, and records analysis. ​
In his spare time, Dr. Rein enjoys reading, music, farming and spending as much time with his family as he can.