The American Mastiff has a much drier mouth than other Mastiffs. The drier mouth is due to outcrossing the English Mastiff with Anatolian Mastiff, which occurred early in the development of the breed. The American Mastiff is a large, massive and powerful dog. Temperament: Dignity rather than gaiety; quiet, calm, loving and loyal. Protective, but not aggressive.

The American Mastiff loves children and is totally devoted to its family. It is non-aggressive except in those instances when its family, especially the children, are threatened. In those instances it becomes a courageous defender. The American Mastiff is wise, kind and gentle, patient and understanding, very loving with its own people, neither shy nor vicious. It is loyal and devoted. Since these dogs are of the Mastiff type and grow to be very large, this breed should only be with an owner who knows how to display strong leadership.The objective in training this dog is to achieve pack leader status.