Valentin Siebenburger is first mentioned in 1531, possibly at the time that he became a master. He had a house in Nuremberg in the upper Schmiedgasse below the castle, where he died in 1564. His wife, Anna, younger daughter of the armourer Wilhelm von Worms the elder, had probably died in 1547.
From 1536 he is frequently found petitioning the City Council to be allowed to employ more than the permitted number of journeymen, because of pressure of work. In 1537/8 he was working for the Stuttgart court, in 1541 for the gentlemen of the Imperial court, and in 1543 for Albrecht, Duke of Prussia. In 1544 he delivered a Rennzeug to Jacob Rosenpusch, the court armourer of the Duke of Prussia. In 1545 he was working for the Emperor Charles V himself. Apart from personal armours, Siebenburger also made munition armours, as when he delivered one hundred armours on the order of the Imperial Master of the Horse, Herr von Andelot, in 1551. Among other things, he refurbished and extended the series of joust armours of the City of Nuremberg.