A young man gazes out from deep shadow, his face softly illuminated against a dark, undefined background. His features are rendered with delicate, lifelike modeling: the light falls across his left cheek, brow, and the bridge of his nose, leaving the right side of his face in near darkness. His lips are gently pressed together, and his expression is calm but alert, with a slight furrow in his brow suggesting concentration or introspection.

Loose curls of brown hair frame his face, catching the light at the top and blending into the shadow below. He wears a dark, reflective breastplate over a white, textured collar, the metal catching a faint glint just below his chin. The background is almost entirely black, with only the faintest hints of brown and ochre, focusing all attention on the sitter's illuminated face and upper chest.

The brushwork is smooth and controlled in the modeling of the face, while the hair and collar are painted with looser, more textured strokes that suggest softness and movement. The composition is tightly cropped, with the head and shoulders filling most of the panel, creating an intimate encounter with the subject. Small details, such as the subtle highlight on the lower lip and the glimmer of the gorget's edge, reveal the artist’s close observation and technical skill.

No secondary figures or objects are visible anywhere in the painting, and the subject appears alone against the background. The upper left and right corners of the painting are almost entirely black, with only a faint transition to brown near the top edge. Light falls most strongly on the left side of the face and collar, while the right shoulder and lower part of the breastplate are enveloped in shadow.

The paint on the background is thinly applied, with subtle variations in tone and barely perceptible brushstrokes that create a soft, atmospheric effect. Self-portrait with breastplate is painted by Rembrandt around 1629.