He attended the Berlinisches Gymnasium zum Grauen Kloster and received a six-month traineeship at Bradford, then a centre of textile manufacture, before he became a partner with his father in 1876.
Though a reserved man, he played an influential role in the German society, especially by his participation at a regular roundtable with Emperor Wilhelm II.
Simon and other invitees like Albert Ballin and Carl Fürstenberg as well as Emil and Walther Rathenau discussed economic life and tried to give the emperor an understanding of a Jewish perspective on social issues.
Their close relationship with the erratic ruler was criticized by Zionist contemporaries and they were later mocked as the "Emperor's Jews" (Kaiserjuden) by Chaim Weizmann.
In 1911, Simon provided the financing of Ludwig Borchardt's excavations at Pharaoh Akhenaten's city in Amarna, and many of the found artefacts, which included the sculpted busts of Nefertiti and Tiye from a court sculptor's workshop outside the main tomb area, became his property.