* Luke Jackson is the main character played by Paul Newman. He is a rebellious young man who is sentenced to a chain gang for a minor crime.
* Paul Newman doesn't use a specific accent in the film. He uses a general American accent with a bit of Southern twang, which is common to many characters in the film. He's not trying to represent a specific region, but rather a type of working-class individual.
It's worth noting that many of the other characters in "Cool Hand Luke" speak with more pronounced Southern accents, which helps to contrast Luke's more casual and slightly less localized speech.