Tom Chaney is a dim witted criminal who killed Mattie Ross's father after he had lost all of his winnings gambling. Chaney shot Frank Ross through the head instantly killing him after a brief drunken argument. Afterwards he stole his horse and money along with two California gold pieces. He fled into the wilderness, later joining and doing several jobs with Luck Ned Pepper's gang. Chaney's weapon is a Henry Rifle with a distinctive rope sling.
In the climax of the film he is killed by Mattie Ross.
Prior to the events of the film he worked as a hired hand for Frank Ross at the family farm in Yell County, Arkansas.