Charles I sits upright on a powerful dun horse, his gloved right hand holding the reins while his left rests lightly on a baton of command. His face is turned slightly toward the viewer, with a composed, distant expression and a neatly trimmed moustache and pointed beard. The horse, with a compact body and unusually small head, lifts its left foreleg as if mid-stride, its mane and tail rendered in flowing, dark curls.

A richly embroidered saddlecloth in deep red hangs beneath the king, edged with gold fringe. To the right, a young page in a vibrant red costume stands partially hidden behind the horse, presenting a helmet to the king with both hands. Behind Charles, dense foliage and the massive trunk of a tree fill the upper right, casting deep shadows and framing the king’s figure.

A gold-fringed tablet tied to a branch above the page reads 'CAROLUS I REX MAGNAE BRITANIAE', identifying the king and asserting his title as ruler of Great Britain. The background opens to a broad, sunlit landscape on the left, with distant trees and a blue sky streaked with clouds, creating a sense of space and grandeur. The brushwork varies from the smooth, careful modelling of the king’s face and armour to looser, more textured strokes in the foliage and ground.

The composition places Charles high in the frame, making him appear elevated and dominant, while the horse’s diagonal stance adds movement and energy. The overall colour scheme balances the warm tones of the horse and earth with the cool blues and silvers of the sky and armour.