The Kentucky Mountain Saddle Horse should be of medium bone and substance, as well as being athletic and refined. They are usually compact, close-coupled, and well-muscled. They have a cob-sized head with a straight profile and broad forehead. The neck is of medium thickness and length, and the withers are flat.

The Kentucky Mountain Saddle Horse is distinguished by its natural four beat gait called an amble, or rack. This smooth, gentle gait can be maintained over rough terrain and has the same footfall pattern as the walk has. The result of this gait is that the rider sits almost motionless astride the horse while it carries the rider at speeds almost as fast as most horses canter. These hardy horses have a calm and kind demeanor. Registered horses must show a gentle and willing disposition; demonstrate evidence of a naturally smooth, even, 4-beat gait under saddle.

These animals may be of any color with white on face, legs, mane, or tail if registered with the Kentucky Mountain Saddle Horse Association (KMSHA), as well as being spotted, having over 36 inches of white if registered with the Spotted Mountain Horse Association (SMHA); the height must not be less than 11 hands (for class B), or 13.3 hands (for class A); must be of good conformation and meet the "breed standard" as adopted and revised in 2006. Foals of KMSHA/SMHA registered sires and dams may be temporarily registered at birth, but must demonstrate the necessary characteristics when they reach an age to be trained under saddle.

The University of Kentucky Equine Parentage Testing and Genetic Research Center has recognized both the Kentucky Mountain Saddle Horse and the Spotted Mountain Horse as individual breeds with distinctive characteristics and genetic DNA markers.