Before getting the part of T-Bag in Prison Break (2005), he considered becoming a
park ranger to support his family, due to the 'phasing out of the
middle-class actor'.
During the filming of Hitman (2007), his Danish co-star Ulrich Thomsen jokingly confided in him that his last name, "knepper", is in fact a dirty word in Danish.
Robert studied drama in Northwestern University (1977-1981).
Graduated from Maumee Highs School in Maumee, Ohio. Was the class of
1977.
Son of a veterinarian in real-life, his character "T-bag" on Prison Break (2005) has a twisted encounter with a veterinarian in Season 1.
He was awarded a 1982 Joseph Jefferson Award Citation for Actor in a Principal Role in a Play for "Class Enemy" at the Next Theatre Company in Chicago, Illinois.
He had the tenor solos in the "Messiah" his senior year at Maumee High School.
Robert and Tori are parents of a boy named Benjamin Peter Knepper (Ben Knepper).
He lives with his family in Los Angeles.
He is of mostly German descent, with smaller amounts of Swiss-German, English, and Scottish ancestry.