Around 1580 he moved to Vienna, where he worked as an assistant to Lucas van Valckenborch, a painter and draughtsman.
[citation needed] Flegel was pupil of Lucas van Valckenborch in Linz from 1582 till 1592.
He is probably the same person Kramm found in Utrecht as ‘juriaen vlegel, Constschilder.’ in the "Protokol" of the notary (or real estate agent) Verduyn, noted as "Acte van 21 Maart, 1616".
[2] If so, then he probably moved there because of the new Utrecht Guild of St. Luke and probably knew other still-life painters active there in that period, such as Roelandt Savery (who had made a trip to Tyrol) and Balthasar van der Ast.
In a period of about 30 years (c. 1600–1630), he produced 110 watercolor and oil pictures, mostly still-life images which often depicted tables set for meals and covered with food, flowers and the occasional animal.