Little is known about the life of Adriaen Thomasz Key. He was born around 1544 and studied with the portraitist Willem Key. He may have been a relative of Key’s or simply taken his name professionally.

Key became a master of the Guild of St. Luke in Antwerp in 1568. Although Key was a registered Calvinist, he is attributed with painting several altarpieces for churches. He is primarily remembered for his portraiture, however, and he is noted for the objectivity with which he portrayed his subjects. Key also worked as a printmaker and made a number of woodcuts.

During Key’s lifetime, Antwerp was the setting for a great deal of political and religious conflict. In the latter half of the 16^th century, Protestant reformers revolted against the rule of the Catholic King Philip II of Spain. After a brief period of secession, Spain regained control of Antwerp in 1585 after a year-long siege. Protestant residents such as Key were given two years to resettle elsewhere, although it appears that Key remained in Antwerp despite his status as a registered Calvinist.

There is no record of Adriaen Thomasz Key after 1589 and his date and place of death are unknown.