I studied math and thought I was going to be an academic but ended up at a brokerage as a quant guy. It was a small to medium size operation so I had a chance to stand out and before too long they wanted me to do some retail and sell some quant based products I developed. They sponsored me for Series 7 and Series 24.
Of the 2 main guys I worked with, one trained as a CPA and one was a geneticist. The geneticist was really ahead of his time. The way he saw the market signal confluence was not mainstream and usually successfully contrarian. Lots of my contacts followed non-traditional routes to their current positions. Perhaps we just mutually gravitated in our associations, but it seems that is not too uncommon these days.
I could post lots more here, but if you want, email me at nbechdel@juno.com if you have more specific questions.