This dissertation offers a new interpretation of Anthony van Dyck’s art and career, taking as its point of departure a body of contemporary anecdotes, poems, and art theoretical texts that all responded to Van Dyck’s portrait sittings. It makes a decisive break with previous scholarship that explained Van Dyck’s focus on portraiture in terms of an intellectual deficit or a pathological fixation on status. Instead, I argue that throughout his career, Van Dyck consciously made the interaction between painter and sitter a central theme of his art. Offering an alternate account of Van Dyck’s relationship to Rubens as a young painter, the opening chapter examines Van Dyck’s initial decision to place portraiture at the heart of his production. I trace that decision to Van Dyck’s work on a series of history paintings that depict the binding of St. Sebastian, interpreted here as a programmatic statement on the part of a young artist with a deep commitment to life study and little interest in an emerging hierarchy of genres that deprecated portraiture. The second chapter surveys the portrait copies of both Rubens and Van Dyck, demonstrating that imitative and historicist investigations link their approaches to portraiture. Van Dyck drew upon his copies of Titian and Raphael in paintings such as his epochal portrait of Cardinal Guido Bentivoglio, which awakened an ambivalent response on the part of Italian artists and critics. But Van Dyck’s practice of imitation also extended to his comportment and self-presentation in public, as exemplified by his emulation of Sofonisba Anguissola. A discussion of Van Dyck’s encounter with Anguissola leads to the contention that Van Dyck saw himself as participating in an alternate genealogy of art that placed court portraiture at the heart of an ambitious career and offered a rare opening to female practitioners. Van Dyck’s reception by one such painter, the English portraitist Mary Beale, provides a Leitmotiv throughout the dissertation. The third chapter situates Rubens’s and Van Dyck’s contrasting approaches to female portraiture within a larger shift in the status of portraits of women in the early seventeenth century, as embodied by the pan-European phenomenon of the “Gallery of Beauties.” This chapter also offers readings of the two artists’ contrasting depictions of Maria de’ Medici, who visited both of their homes during her exile in the Southern Netherlands. Such visits to Van Dyck’s studio provide the subject of the fourth and final chapter, which reexamines early biographers’ accounts of Van Dyck’s sittings and surveys his legacy for English painting and art theory over the course of the long seventeenth century. Whereas in their own writings, artists emphasized the opportunities for courtly self-assertion afforded by the sitting, poets and playwrights were more likely to depict sittings as threats to the sexual and moral order. Both attitudes represent important aspects of Van Dyck’s critical reception. The conclusion looks ahead to the tenacious hold of the portrait sitting on modern imaginings of the studio. Examining the portrait practices of such artists as Lucian Freud, Andy Warhol, and Alice Neel, the conclusion reveals the persistence of a fascination with the sitting that had its origin with Van Dyck.