I would argue that Randolph is the character in The Clearing who has the most in common with Grant in A Lesson Before Dying.
Randolph is depicted as a hard worker and someone who tries to right wrongs by bringing his brother, Byron, back into the family after an estrangement. Randolph is dedicated to his work of clearing the swamp and is undeterred by the weather, the terrain, and the consistently tense atmosphere surrounding the camp. Randolph is the type of man who will take charge, which is evidenced by his acting on the decision to close down the local saloon, despite what the local Mafia members will have to say about it.
Although his story is completely different, Grant Wiggins in A Lesson Before Dying is also the type of man to take control and to attempt to bring justice and harmony to any situation. He takes the time to help Jefferson, a young Black man falsely convicted of murder, become emotionally prepared to face the electric chair.
Like Randolph, he shows determination in the face of adversity, because Jefferson initially wants nothing to do with him. He is also attempting, as best he can, to right a wrong, although getting Jefferson's sentence overturned is out of the question. He has taken charge and is doing his best to help Jefferson.