Joseph was the youngest son of Bernhard von Köhl and grew up like his 3 other brothers at Paradiesplatz in the Paradieshaus. He also received a good education, studied medicine and philosophy in Italy at the University of Padua and graduated with a doctorate in 1687.
He then returned to Chur and practised as a doctor. He was also an important support to his father in his business. In 1693 Joseph was admitted to the Rebleute guild. After 1695 he married Anna Catherina von Tschudi (1663-†1749), who came from a good family. The couple lived in the Paradieshaus and had 2 children, but they died shortly after birth. There were to be no further children.
After his father's death, Joseph continued to look after the Köhl trading house and practised as a doctor. In addition, he now also managed the assets of the community of heirs, and his father had also appointed him as the bailiff of his younger sister. All these tasks must have kept him fully occupied. Thus he did not aspire to any offices in the city administration. Joseph now held his protective hand over his siblings and their children, as his father had done.
His father had decreed that the man advantage should apply to his inheritance. The brothers had therefore inherited all the goods and could dispose of them. They were therefore also liable to pay taxes. In 1713 his eldest brother Peter died, and in 1727 his older brother, Pastor Bernhard Köhl, was to follow. The entire tax burden now lay with him. This, and the fact that he himself had no descendants, probably prompted him to change his father's decree.
His father's inheritanceAccording to the 1729 tax roll, the inheritance of Bernhard von Köhl was divided as follows:
Total 176.62 gulden. The 3 still living children of Bernhard von Köhl, 15 grandchildren and 1 widowed wife of one of the grandchildren were entitled to inherit.
After this division, Joseph's tax burden was significantly reduced. In 1727 he paid 34.17 guilders for the inheritance, in 1730 only 5.22 guilders. He continued to take over the tax debts for his sister-in-law, Susanna Margadant-Reidt, as she probably had too few means. Joseph could well afford this - in 1733 his assets were assessed at 27199 guilders, for which he had to pay 9 guilders in taxes.
In 1748 his last sibling, Anna Catharina Köhl-Mattli, died. In 1749 his wife Anna Catherina von Tschudi also followed. Joseph was to follow his wife only 1 year later. He died in his house on Paradisgasse, where he had spent his entire life, at the ripe old age of 87. His nephew Johann Antoni Terz noted in his family book: "A[nn]o 1750: den 24. Augusty. H[er]r Öchheim, Vnd G[e]f[atter] Doctor Josepf Köhl died in the 87th year of his age. He had such a face1 that he could read and write without a mirror2."3
What happened to his property after his death is not known. Since Jospeh himself had no descendants, his nephew, head guild master Bernhard Köhl, presumably inherited many of his estates. For that was what Mayor Bernhard Köhl had wished in his last will.
And head guild master Bernhard Köhl was now the only living male descendant of Mayor Köhl. And he had already fathered a large flock of descendants. Of 14 children born, 7 were still alive. More were to come and save the Köhl family from extinction. Bernhard Köhl had also received the original letter of nobility and the will of his grandfather. He was to take good care of it and pass it on to his son Sebastian Köhl.