Michel Sittow was born about 1469 of German-Scandinavian stock in the Hanseatic port city of Reval, now Tallinn, in Estonia. He probably received his earliest training in Reval from his father, also a painter, yet his apprenticeship in Bruges and years of work for Queen Isabel of Castile and for allied courts gave his art a Flemish and cosmopolitan flavor.
Sittow moved to Bruges in the spring in 1484. The assumption that he studied with Memling rests only on that artist's position as the leading painter in Bruges and on Sittow's use of Memling's Madonna types. He did not register as a master with the Bruges guild and his whereabouts are unknown before 1492 when he entered the service of Isabel the Catholic. Sittow appears to have been identical with the painter "Melchoior Aleman" also mentioned in Isabel's household accounts.
At the Spanish court he was prized as a portrait painter. He is known to have collaborated with Juan de Flandes on the series of small panels of the lives of Christ and the Virgin for Isabel. While he remained in Isabel's service until her death in 1504, he was apparently absent from Spain after late 1502. Suggestions that he visited the courts of Margaret of Austria and Henry VII of England shortly after 1502 cannot be substantiated. He was in Brabant at the end of 1505 or early in 1506, working for Philip the Fair. He returned to Reval in 1506 to settle his inheritance and remained there, receiving membership in the artists' guild late in 1507 and marrying in 1509. He was called away from Reval in 1514 to paint the portrait of Christian II of Denmark, the future husband of Margaret of Austria's niece, Isabella. Sittow then began a second, shorter period of service at the court of Margaret of Austria and her nephew Charles V in the Netherlands. This was interrupted by a brief trip to Spain to negotiate the salary still owed him. By 13 July 1518, when he married again, Sittow was back in Reval. He lived there, a prosperous and respected citizen, until his death in late December of 1525. 
 His wife is mentioned as a widow as of 1 January 1526.
[Hand, John Oliver, and Martha Wolff. Early Netherlandish Painting. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1986: 228.]
Winkler, Friedrich. "Zittoz, Miguel." In Thieme-Becker 1947, 36:531-534.
Friedländer, Max J. "Ein neu erworbenes Madonnenbild im Kaiser-Friedrich-Museum." Amtliche Berichte aus den königl. Kunstsammlungen 36 (1915): cols. 177-183.
Friedländer, Max J. "Neues über den Meister Michiel und Juan de Flandes." Der Cicerone 21 (1929): 249-254.
Johansen, Paul. "Meister Michel Sittow, Hofmaler der Königin Isabella von Kastilien und Bürger von Reval." Jahrbuch der königlich Preussischen Kunstsammlungen (Jahrbuch der Berliner Museen) 61 (1940): 1-36.
Trizna, Jazeps. Primitifs flamands. Contributions. Michel Sittow, peintre revalais de l'école brugeoise (1468-1525/1526). Brussels, 1976.
Hand, John Oliver and Martha Wolff. Early Netherlandish Painting. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1986: 228.