A full-length figure stands upright against a dark, nearly featureless background, his body turned slightly to the left while his gaze is directed forward. He wears a richly decorated black coat trimmed with elaborate gold embroidery, a white shirt with a high collar, and a broad red sash tied at the waist, its ends falling to the side in thick folds. His left hand grips a slender cane, its tip resting on the floor, while his right hand holds a bicorne hat adorned with a white plume and a white glove draped over the brim.

The figure's chest is adorned with several orders and decorations, including a prominent star and cross, their metallic surfaces rendered with sharp highlights that catch the light. White stockings and black shoes with gold buckles complete his attire, and the shoes are positioned firmly on a subtly textured wooden floor that recedes into shadow. The face is painted with careful attention to the ruddy complexion and curling brown hair, while the expression is serious, with lips pressed and eyes focused ahead.

Light falls from the left, illuminating the right side of his face and the intricate patterns of his uniform, while the background remains in deep shadow, emphasizing the figure's presence. The brushwork is smooth in the rendering of the face and hands, while the gold embroidery and the folds of the sash are painted with more visible, textured strokes that suggest movement and depth. The composition is vertical and monumental, with the figure occupying almost the entire height of the canvas, reinforcing his stature and importance.

Small details, such as the lace edging at the cuffs and the glint of the gold tassels on the sash, are carefully described, adding richness to the portrayal. Portrait of the Duke of San Carlos was painted by Francisco de Goya in 1815. Goya depicts the Duke in formal attire, emphasizing his status and the honors he received, as seen in the array of decorations across his chest.