Two young men stand together in a shallow architectural space, their bodies close but their gazes apart. On the left, a figure in gold and brown silk stands on a step, leaning his left arm on a stone plinth and looking past the viewer into the distance. His doublet and breeches are made of shimmering fabric, trimmed with lace at the collar and cuffs, and his long fair hair falls to his shoulders.

Both wear high leather boots with spurs, and the figure on the right also carries a sword at his side. The background is a muted brown, which sets off the rich colours and textures of their clothing, and the light falls softly across the scene, highlighting the sheen of satin and the crispness of lace. The brushwork is smooth and precise, especially in the rendering of the fabrics, which show subtle variations in light and shadow.

The composition places the brothers close together, yet their opposed postures and divergent eyelines suggest a sense of individuality and tension. The right figure wears a shimmering blue cape with silver trim, draped over his left shoulder and arm. His left hand is gloved in white leather, with the glove's fingers elegantly splayed and visible against his blue breeches.

The stone plinth at the left edge of the painting has a sharply defined corner and a pale, smooth surface. The floor beneath the figures is rendered in warm brown tones, with subtle brushwork suggesting a hard, flat surface. There are no secondary figures or objects in the background, which is an empty expanse of brown and tan.

The light source comes from the left, casting soft shadows behind the figures and illuminating the folds of their garments. The lower right corner of the painting shows the shadow of the right figure's boot, grounding him in the space. The handling of paint in the blue satin breeches and cape creates a highly reflective, almost metallic effect with crisp highlights and deep shadows. Lord John Stuart and His Brother, Lord Bernard Stuart was painted by Anthony van Dyck in 1638.