Tenpenny graduated with a Bachelor of Arts from the University of Toledo in 1980, and subsequently received a Doctor of Osteopathic Medicine degree from the Kirksville College of Osteopathic Medicine in Missouri in 1984. From 1986 to 1998, Tenpenny was the director of the emergency department at Blanchard Valley Hospital in Findlay, Ohio. She opened an osteopathic practice in 1994, and went on to establish two more such practices, in 1996 and 2011.