Jangmo-o is a small, quadrupedal Pokémon similar to a dinosaur. The lower half of its body is black, while the upper half is light gray. It has a beak-like snout with a small, tooth-like spike in each corner of its lower jaw and big, red eyes. On the front of its head is a large, heart-shaped yellow scale. A small tuft similar to ears or small feathers extends from the back of its head on either side, and there is another small, white tuft on its chest. Six teardrop-shaped, loose-hanging scales form a half ring around its shoulders. These scales are gray with pale yellow along the outside edge. A solid yellow scale of the same shape is on the tip of its tail. Each of its feet has three yellow claws.
While Jangmo-o trains diligently and remains humble, it has the pride of a warrior. It employs the scale on its forehead for both attack and defense, so it never shows its back to its foe. Many Trainers take this behavior as proof of this Pokémon's valiant nature. Jangmo-o lives and trains with others of its kind in harsh areas that are far away from other Pokémon and people. The scales on its body make a metallic sound when struck and are used to express emotion, communicate with others of its kind, and intimidate opponents.