The sitter is depicted as having a homely face—widely spaced and flat—with a small nose and thin lips. The lack of idealised beauty has led to a general belief that this work was painted on commission, although it is possible that the model was Vermeer's daughter. The artist probably used a live model but, as with Girl with a Pearl Earring, did not create the work as a portrait, but as a tronie, a Dutch word meaning "visage" or "expression", a type of Dutch 17th-century picture appreciated for its "unusual costumes, intriguing physiognomies, suggestion of personality, and demonstration of artistic skill". The picture encourages the viewer to be curious about the young woman's thoughts, feelings, or character, something typical in many of Vermeer's paintings.
 
Girl with a Pearl Earring and Portrait of a Young Woman are unusual for Vermeer in that they lack his usual rich background; instead the girls are framed by a background of deep black. This isolating effect seems to heighten their vulnerability and seeming desire to place trust in the viewer. In 1994, the art historian Edward Snow wrote that Portrait of a Young Woman conveys "the desire for beauty and perfection into a loving acceptance of what is flawed".