Nothing is known about Dr. Holt's life prior to or as the outbreak began, other than he was primary care doctor and spent time working in the oncology ward.
Dr. Holt is among the Pioneers who helps Virginia split up the members of the caravan. He also helps care for Grace and takes her away for re-settlement. Shortly after departing from the Humbug's Gulch, he radios Virginia and informs her that Grace is not sick, but rather 3-4 months pregnant.
This list shows the victims Dr. Holt has killed:
- Possibly numerous counts of zombies
- Despite having speaking lines in "End of the Line", Dr. Holt remained uncredited.