A man stands at three-quarter length against a deep red backdrop, his pale face turned slightly toward the viewer, with a composed and direct gaze. His hair is parted at the center and falls in soft waves to his jaw, framing a prominent nose and a carefully groomed mustache. He wears a high, stiff white collar that contrasts sharply with his dark, voluminous garment, which is rendered in deep, nearly black tones.

His left hand, ungloved and pale, extends downward to hold a white letter, its crisp edge contrasting with the deep black of his sleeve. The background is a rich, almost theatrical red, with a geometric form at the right edge that hints at a draped curtain or a piece of furniture, while a sliver of greenish-grey at the far right suggests an opening or a window. The brushwork is smooth and controlled, especially in the modeling of the face and hands, while the fabric of the sleeve is painted with more visible, fluid strokes to evoke its sheen and texture.

The composition is carefully balanced, with the figure occupying most of the canvas, his head and shoulders set slightly left of center, and the objects he holds arranged to lead the viewer’s attention from his face to his hands. The museum's record identifies the objects in the sitter's hands as a letter, a sword, and a glove, all of which are visible in the composition. The restrained palette, the dignified pose, and the attention to the textures of fabric and flesh are characteristic of Velázquez’s approach to royal portraiture in this period.