Jan Boeckhorst was born in Münster in 1604. He became a canon in the Jesuit church when he was seventeen and apparently did not turn to painting until he was twenty-two years of age. He moved to Antwerp in the mid-1620s, probably to study with Peter Paul Rubens. Cornelis de Bie writes that Boeckhorst, who was nicknamed "Lange Jan" ("Tall Jan"), also trained briefly with Jacob Jordaens (1593-1678) because Rubens was in Spain and England at the end of the 1620s. Documentary and visual evidence also indicates that Boeckhorst worked closely with Anthony van Dyck, presumably during the latter's stay in Antwerp from 1627 to 1632. Not only did the two artists collaborate on individual works of art, but Boeckhorst also made copies of Van Dyck's paintings.
Boeckhorst, who became a master in the Saint Luke's Guild in Antwerp in 1633/1634, assisted Rubens on the decorations for the Pompa Introitus Ferdinandi. Boeckhorst, following the example of Rubens and Van Dyck, traveled to Genoa and Venice in 1637, where he was able to study masterpieces by Titian, Tintoretto, and Veronese. After returning to Antwerp, he assisted Rubens again, this time with the large commission he had received to execute mythological paintings for Philip IV's hunting lodge, the Torre de la Parada. In November 1639 he returned to Italy, this time to Rome, although he may also have traveled to Naples and Sicily.
The date of Boeckhorst's return to Antwerp is not known, but it was probably in the early 1640s, as he painted a number of portraits and altarpieces during that decade. In 1649 he was invited to be court painter for Queen Christina of Sweden, but he apparently never went to Sweden to assume that position. He remained active as a painter in Antwerp, executing altarpieces not only for churches in provincial cities in the southern Netherlands but also for his native Münster. During the latter years of his career he painted a number of allegorical and mythological paintings and designed illustrations for religious books published by the Plantin Press. Boeckhorst died in Antwerp on 21 April 1668 and was buried in the collegiate Saint Jacobskerk three days later. [This is an edited version of the artist's biography published in the NGA Systematic Catalogue]
 Although Boeckhorst is never listed as a student of Jordaens, he is mentioned as such by Cornelis de Bie, Het Gulden Cabinet van de edele vry schilderconst, Antwerp, 1661: 254 (reprint Soest, 1971), as quoted by Helmut Lahrkamp, "Zur Biographie des Malers Jan Boeckhorst," in Paul Huvenne, et al., Jan Boeckhorst 1604-1668: Maler der Rubenszeit, exh. cat., Westfälisches Landesmuseum für Kunst und Kulturgeschichte, Münster; Rubenshuis, Antwerp; Freren, 1990: 13. See also Johann Bockhorst. Der Maler aus Münster zur Zeit des Westfälischen Friedens, exh. cat. Stadtmuseum Münster, 1998.
 See Hans Vlieghe in Münster 1990, 81-83.
 For a discussion of these issues, see Helmut Lahrkamp in Münster 1990, 13-15.
Lahrkamp, Helmut. "Der 'Lange Jan': Leben und Werk des Barockmalers Johann Bockhorst aus Münster." Westfalen. Hefte für Geschichte, Kunst und Volkskunde 60 (1982): 3-22.
Huvenne, Paul, et al. Jan Boeckhorst 1694-1668: Maler der Rubenszeit. Exh. cat. Westfälisches Landesmuseum für Kunst und Kulturgeschichte, Münster; Rubenshuis, Antwerp. Freren, 1990.
Johann Bockhorst. Der Maler aus Münster zur Zeit des Westfälischen Friedens. Exh. cat. Stadtmuseum Münster, 1998.
Wheelock, Arthur K., Jr. Flemish Paintings of the Seventeenth Century. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 2005: 5.