In Costume of the Reign of King Henry III, Charles Hamilton Smith presents a detailed representation of royal attire. The painting features rich colors, including deep reds and golds, which signify the opulence of the period. The figure depicted is adorned in elaborate garments, showcasing intricate patterns and textures.

The background is minimal, focusing attention on the costume itself. The painting is executed in oil on canvas, a common medium for detailed costume studies of the time. The brushwork is precise, allowing for a clear depiction of the fabric and embellishments. The dimensions are approximately 60 x 80 cm, making it a manageable size for viewing in a gallery.

The work exemplifies the academic style prevalent in the early 19th century. Charles Hamilton Smith was known for his interest in military and historical subjects, often focusing on costume and attire. This particular work reflects his dedication to historical accuracy, as he aimed to capture the essence of King Henry III's reign. An interesting fact about this painting is that it serves as a valuable reference for historians studying medieval fashion.

Smith's works are often celebrated for their detail and educational value.