A muscular figure stands at the left, seen from behind, his body twisted as he raises a heavy club above his head. He wears only a yellow cloth tied at his waist, leaving his back, arms, and legs exposed to the light that falls from the upper left. In front of him, another nude male figure crouches low to the ground, his body turned away and his head ducked, as if bracing for a blow.

The two figures are set in a rocky, shadowed landscape, with dark trees framing the scene on both sides and a glimpse of distant architecture and blue sky visible through an opening at right. The light carves out the muscles and limbs of both bodies, highlighting their tension and the drama of the encounter. The ground is strewn with stones and the earth is painted in deep browns and ochres, while the background recedes into cooler greens and blues.

Zurbarán uses bold, sculptural brushwork to model the flesh, with smooth transitions in the skin tones and sharper contrasts in the shadows. The composition is tightly focused on the confrontation, with the standing figure dominating the left half and the kneeling figure compressed into the right foreground. Hercules defeats King Geryon was painted by Francisco de Zurbarán in 1634, during the height of the Baroque movement. Zurbarán's approach here reflects the Baroque interest in powerful movement, strong contrasts of light and shadow, and the expressive potential of the human body. The artist's handling of paint emphasizes the physicality of the figures, with visible brushstrokes that give texture to the flesh and landscape alike.