Born in Germany, Fritz Cassirer travelled widely through Europe, Russia and Siberia, and visited America for the first time in 1911 where he stayed at the same address as Franz, thereby identifying him as brother. 5'9", fair, b rown hair, blue eyes. He had a long-standing interest in precious stones and visited South America and Canada as well in pursuit of this interest. He worked with the Mining Academy in Freiberg, Germany, the Museum of Natural History in London, and mineralogical departments of the museums in Prague and Paris, the Smithsonian Institutein the US, and then the American Museum of Natural History in New York.

In America Fritz lived in New York after leaving Germany. He was a successful business man, basing his activities around his interests in precious jewels and art.

However, Werner Falk recounts that Fritz was never happy about the way in which his family had dealt with its money.774 In 1923 Max Cassirer decided that it was the moment to convert the family fortune of around 11 million Swiss francs, into German reichmarks hoping that the inflation would now reverse and believing it was the patriotic thing to do and Fritz’s father followed this, as it turned out, bad advice. The young Fritz protested but to no avail, and by 1925 the family fortune had dwindled to nothing.

For Fritz this meant the undoing of the things that should have come to him since he had been trained by Isidor to take over that factory and had been sent to America to study other factories and related business practice. Fritz's life after the factory had been sold was confronted thus by one crisis after another. He had lost the job for which he had been trained, and also lost the money that he otherwise could have expected when he was in his late 20's. His life was a sequence of attempts to reconstitute these things things and in his last years in Berlin, from 1920 after the war years, to 1933 when he emigrated to America, he took on a range of interesting jobs. He was for a few years the Managing Director of the German theatre and also Producer, Reinhardt's, Business Manager. He went into the advertising business and had a contract with the Red Flag (Rote Farne) which was the Berlin Communist paper, to deal with all its commercial advertising. All commercial advertising in the Red Flag went through Fritz.