According to Forbes, here's where it started.
So, he taught math at a prestigious private school in Manhattan. Hired by AG Barr's father (honestly, this is just a weird coincidence, not a conspiracy).
Not mentioned above is that he didn't have a degree and was eventually fired.
The whole read is fascinating: https://www.forbes.com/sites/lisettevoytko/2019/07/12/jeffrey-epsteins-dark-faade-finally-cracks/