Although his career was brief, lasting a mere 10 years, Vincent van Gogh proved to be an exceptionally prolific and innovative artist. While he experimented with a variety of subjects—landscape, still life, portraiture—it is his self–portraits that have come to define him as an artist. Like his predecessor, Rembrandt van Rijn, Van Gogh was a devoted and probing practitioner of the art of self–portraiture. He painted no fewer than 36 self–portraits, undertaking his first forays just after his arrival in Paris in March 1886 and executing his last, culminant works during his stay at the asylum of Saint–Paul–de–Mausole in Saint–Rémy. The Washington canvas is one of the very last self–portraits Van Gogh painted.
During the first months of his voluntary internment at the asylum, the artist showed little interest in figure painting and concentrated instead upon the surrounding landscape. But in early July 1889 while painting in the fields near the asylum, Van Gogh suffered a severe breakdown that could have been a symptom of epilepsy. Incapacitated for five weeks and greatly unnerved by the experience, the artist retreated to his studio, refusing to go out even to the garden. This painting is the first work he produced after recovering from that episode. In a letter to his brother Theo written in early September 1889, he observed:
They say—and I am very willing to believe it—that it is difficult to know yourself—but it isn't easy to paint yourself either. So I am working on two portraits of myself at this moment—for want of another model—because it is more than time I did a little figure work. One I began the day I got up; I was thin and pale as a ghost. It is dark violet–blue and the head whitish with yellow hair, so it has a color effect. But since then I have begun another one, three quarter length on a light background. 
This self–portrait is a particularly bold painting, apparently executed in a single sitting without later retouching. Here Van Gogh portrayed himself at work, dressed in his artist's smock with his palette and brushes in hand, a guise he had already adopted in two earlier self–portraits. While the pose itself and the intense scrutiny of the artist's gaze are hardly unique—one need but think of the occasionally uncompromising self–portraits of Rembrandt—the haunting and haunted quality of the image is distinct. The dark blue–violet of the smock and ground, the vivid orange of his hair and beard, create a startling contrast to the yellow and green of his face and heighten the gauntness of his features in a sallow complexion. The dynamic, even frenzied brushwork lends an uncommon immediacy and expressiveness to his portrayal. In its sheer intensity, it stands in sharp contrast to the other self–portrait he painted at the same time (Musée d'Orsay, Paris) in which the artist appears calmer and more self–possessed. Nevertheless, Van Gogh preferred the Washington painting as the one that captured his 'true character." 
(Text by Kimberly Jones, published in the National Gallery of Art exhibition catalogue, Art for the Nation, 2000)
1. Letter no. 604, The Complete Letters of Vincent Van Gogh, 3 vols. (London, 1958), 3:201-202. 2. Letter no. W14, Van Gog 1958, 3:458.