The movie version of Sign of the Beaver was originally entitled Keeping the Promise. It is interesting because it focuses on different things than the book. A lot more emphasis is given to the family situation of the central character, Matt Hallowell. The events happening to the Hallowell parents and siblings are chronicled alongside what is happening to Matt, whereas in the book the family's experiences are only described in the beginning and at the end. In the movie, Matt's mother and siblings were to have been escorted to the Maine homestead by Matt's father's irresponsible brother Ethan, but Ethan backs out at the last minute, making it necessary for Matt to stay on the land holding alone while his father goes back to fetch the rest of the family. In the book, the family had planned originally for Matt to stay alone, and there is no mention of Uncle Ethan.

In the book, Matt is found by Saknis and Attean after a dangerous encounter with bees, but this part is not in the movie. Instead, Matt is hurt when he goes after an unscrupulous trapper, called Ben in the book but Loomis in the movie, who takes advantage of his hospitality and steals his father's gun. Saknis and Attean save his life in both versions, but, obviously, from different accidents. Also, in the book, Matt and Attean reach an understanding after an encounter with a bear, but in the movie, the fateful encounter is with Loomis, who is caught in a trap. In the book, Matt is greeted with hostility from Attean's grandmother when he goes to the Indian village, but in the movie, the hostility comes from the young men in the tribe.

Ben, or Loomis, does not play a part in the second half of the book, and actually does not appear after his initial encounter with Matt. In the movie, however, it is Loomis who saves Matt's family in the snow and brings them to the cabin. The invitation to come with the Indians as they leave their Penobscot River home comes from Sakniss in the book, but in the movie, it is Attean who instigates the offer. In the book, Matt gives Attean his grandfather's watch as a parting gift, but in the movie, he gives him his copy of Robinson Crusoe.