The way Donald J. Trump tells it, his first solo project as a real estate developer, the conversion of a faded railroad hotel on 42nd Street into the sleek, 30-story Grand Hyatt, was a triumph from the very beginning.

The hotel, Mr. Trump bragged in “Trump: The Art of the Deal,” his 1987 best seller, “was a hit from the first day. Gross operating profits now exceed $30 million a year.”

But that book, and numerous interviews over the years, make little mention of a crucial factor in getting the hotel built: an extraordinary 40-year tax break that has cost New York City $360 million to date in forgiven, or uncollected, taxes, with four years still to run, on a property that cost only $120 million to build in 1980.

The project set the pattern for Mr. Trump’s New York career: He used his father’s, and, later, his own, extensive political connections, and relied on a huge amount of assistance from the government and taxpayers in the form of tax breaks, grants and incentives to benefit the 15 buildings at the core of his Manhattan real estate empire.

Since then, Mr. Trump has reaped at least $885 million in tax breaks, grants and other subsidies for luxury apartments, hotels and office buildings in New York, according to city tax, housing and finance records. The subsidies helped him lower his own costs and sell apartments at higher prices because of their reduced taxes.

Mr. Trump, the Republican nominee for president, has made clear over the course of his campaign how proud he is that “as a businessman I want to pay as little tax as possible.”

While it is impossible to assess how much Mr. Trump pays in personal or corporate income taxes, because he has refused to release his tax returns, an examination of his record as a New York developer shows how aggressively he has fought to lower the taxes on his projects.

Mr. Trump successfully sued the administration of Mayor Edward I. Koch after being denied a tax break for Trump Tower, his signature building on Fifth Avenue. Two decades later, in a lawsuit that spanned the administrations of Mayors Rudolph W. Giuliani and Michael R. Bloomberg, he won a similar tax break for Trump World Tower, a building on First Avenue with some of the city’s highest-priced condominiums in 2001.

The tax breaks for those two projects alone totaled $157 million.

The tax break at the 44-story Trump International Hotel and Tower at Columbus Circle came to $15.9 million.

No possible subsidy was left untapped. After the terrorist attacks on the World Trade Center, Mr. Trump lined up a $150,000 grant for one of his buildings near ground zero, taking advantage of a program to help small businesses in the area recover, even though he had acknowledged on the day of the attacks that his building was undamaged.

“Donald Trump is probably worse than any other developer in his relentless pursuit of every single dime of taxpayer subsidies he can get his paws on,” saidAlicia Glen, Mayor Bill de Blasio’s deputy mayor for housing and economic development, who first battled Mr. Trump when she worked in Mr. Giuliani’s administration.

In seeking those subsidies, Mr. Trump is not that different from many other developers. But the level of subsidies he has received along with his doggedness in claiming them seem at odds with his rhetoric as an outsider candidate who boasts of his single-handed success and who has denounced what he calls the pay-to-play culture of politics and a “rigged” system of government.

Without addressing specific questions about his pursuit of tax breaks and other subsidies, Mr. Trump in a telephone interview defended going after them. “In many cases, they made the difference between building and not being able to build,” he said. “I’ve gotten incentives in other parts of the world as well.”

An Unprecedented Break

In the mid-1970s, eager to make his mark in Manhattan, the 30-year-old Mr. Trump focused his attention on the failing Commodore Hotel on East 42nd Street, next to Grand Central Terminal. The owner, the bankrupt Penn Central Railroad, was keen to sell.

It did not seem like an auspicious plan. The city was in the midst of both its own fiscal crisis and a broader economic one; the neighborhood near the terminal had gotten seedy; and Mr. Trump did not have the capital for the project. He needed his father, Fred C. Trump, to guarantee a portion of the construction loan. Hyatt, which was going to run the hotel, took a 50 percent stake in exchange for guaranteeing the rest of the project.

But Mr. Trump insisted that the project was not viable without a tax break from the city.

In pressing for government approval, Mr. Trump proved to be the quintessential insider, at least through his father: The elder Mr. Trump was a major contributor to and friend of Mayor Abraham D. Beame and Gov. Hugh L. Carey, both Democrats.

“Fred was a big macher in Brooklyn,” said Martin J. McLaughlin, a lobbyist who worked for Donald Trump in the 1990s. “He had an extremely close relationship with Beame and Carey.”

Mr. Trump visited a young city official, Michael Bailkin, who devised a plan centered on a 40-year tax abatement, still the longest ever granted by the city, under which the state would own the land beneath the hotel and lease it to the partnership for $1 a year.

Mr. Trump said the decision was made on the merits. “We were a contributor like many people were contributors,” he said. “But there never was a quid pro quo.”

Even before it opened, though, Mr. Trump had infuriated the new mayor, Mr. Koch, by reneging on the promise to allow for access to the subway on the east and west sides of the hotel.

Mr. Trump eventually granted the western easement and allowed the Metropolitan Transportation Authority to build a stairwell, but shed his responsibility for the other entryway.

City officials initially estimated that the tax break on the Hyatt was worth $4 million a year to Mr. Trump. But according to a recent analysis conducted by the city’s Finance Department at the request of The New York Times, the actual annual giveaway was far higher: $6.3 million in 1983, rising to $17.8 million in 2016. The combined value of the forgiven taxes is $359.3 million, with four years left on the abatement.

Over the same period, the hotel’s owners have paid the city $202.5 million in rent and fees, according to the state agency overseeing the project, Empire State Development.

Mr. Trump said the tax break did what it was supposed to do. “The hotel was a great success for the city,” he said. “It regenerated interest in that area.”

But early on, the city suspected something was amiss with the rent payments, when the total dropped in 1986, despite rising profits. A 1989 review by Karen Burstein, the city’s auditor general at the time, found that Mr. Trump and Hyatt owed the city $2.9 million for 1986, having used “aberrant and distortive” accounting methods to reduce their obligation.

“This was subsidized by city residents,” Ms. Burstein said recently of the tax break. “The last thing you do is cheat the very people who are your partners.”

After the city and state demanded payment, the hotel partners sued them in 1990. The suit was settled in 2004. Neither court files nor the city’s Law Department have a copy of the agreement, but a city official who requested anonymity because the person was not authorized to discuss the matter, said that the city recouped $850,000.

Low Taxes, ‘Elegant Life’

When the Hyatt opened, Mr. Trump was already at work on a second project: Trump Tower, the 58-story, bronze-glass building that would become his home, the headquarters for his company and a tourist attraction.