Father: Donald Knepper.

During 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).

Son-in-law of Peter V. Herald.

Mother: Pat Deck (died in 2003).

He lives with his family in Los Angeles.

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'.

Brother-in-law of Michael Herald.

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 has a twisted encounter with a veterinarian in Season 2.

Robert and Tori are parents of a boy named Benjamin Peter Knepper.