For more than a decade, New York taxi industry leaders got rich by creating a bubble in the market for the city permits, known as medallions, that allow people to own and operate cabs.

In several articles this year, an investigation by The New York Times found that government officials stood by as industry leaders artificially inflated medallion prices and channeled immigrant drivers into loans they could not afford to purchase the permits. The leaders reaped hundreds of millions of dollars before the bubble burst, wiping out thousands of buyers who are still mired in debt today.

And no one embodies the glittery rise, unfettered recklessness and spectacular collapse of the industry more than Mr. Freidman.

A Russian immigrant and a cabdriver’s son who got his nickname by building the city’s biggest fleet, Mr. Freidman was a primary architect of some of the tactics used to build the bubble, according to records and interviews. At the height of the market, he had accumulated $525 million in assets. He befriended the filmmaker Spike Lee, the baseball star Mo Vaughn and Mayor Bill de Blasio. His outsize antics and lavish spending often landed him on Page Six, the New York Post’s gossip column.

As a generation of cabdrivers became trapped in overwhelming debt, Mr. Freidman created offshore trusts that protected some of his money when the bubble burst, records show. While his business partners lost millions because of his tax fraud, Mr. Freidman avoided prison by cooperating with a federal investigation into one of his partners, Michael D. Cohen, President Trump’s former lawyer.