A grandson of the literati painter Kang Se-hwang (姜世晃, 1713–1791), Kang I-o (姜彝五, 1788–1857) served in several government posts. This portrait of Kang I-o has been passed down in the family together with a portrait of Kang Se-hwang. Both portraits feature a half-length depiction of the sitter clad in an official uniform and facing the viewer. The upper portion of Portrait of Kang I-o bears an inscription reading “Painted by Sodang” (小塘寫). This is the sobriquet of Yi Jae-gwan (李在寬, 1783–1849), who was a commoner literary figure and painter active in the early nineteenth century. The eulogy in the upper-right section of the painting was written by Kim Jeong-hui (金正喜, 1786–1856), who was celebrated for his Chusa calligraphic style. In the center of the composition is a half-length image of Kang I-o wearing a black samo (official’s silk winged hat) and a pink sibok (official’s everyday robe without rank badges). Drawing lines were only rarely used in the depictions of his facial features and the bone structure of his face, since it is difficult to delineate a frontal view with lines alone. Instead, his facial features and bone structure are portrayed with soft shading created through the application of dry brushstrokes to the edges of the face and the areas near the eyes, nose, and mouth. Such techniques employed by Yi Jae-gwan, the author of this portrait, were influenced by Yi Myeong-gi (李命基, 1756–1813), a leading figure in the production of portraits during the reign of King Jeongjo (正祖, r. 1776–1800). In this work, the pink sibok worn by Kang I-o is rendered in lines with varying thicknesses and ink tones. Shading is created by reapplying dark pink over light pink along the drapery folds. Kang is also shown wearing a sapgeumdae (belt with gold ornaments) that indicates the second rank in the bureaucratic hierarchy. The frontal ornament on the belt is adorned with ornate three-dimensionally rendered designs and the addition of gold leaf. Based on these features, Portrait of Kang I-o is viewed as one of the most remarkable examples of the early nineteenth century style. It is also significant as the sole surviving demonstration of Yi Jae-gwan’s skills as a painter.