Joe Pantoliano ended up being the perfect choice for the role of Teddy in Memento, but Christopher Nolan initially didn’t want to cast him for one reason in particular. Memento stars Guy Pearce as Leonard Shelby, a man with short-term memory loss who uses a series of tattooed clues to track down his wife’s killer. Pantoliano plays John Edward Gammell, better known simply as Teddy, a contact who initially seems to help Leonard in his investigation, but – based on a note Leonard left for himself on an annotated Polaroid – might not be trustworthy.
https://screenrant.com/memento-joey-pantoliano-casting-christopher-nolan-perfect/