The tycoon is estimated to have a net worth of US$3.7 billion (S$5.2 billion) in 2016, according to Forbes. The next richest is US founding president George Washington at US$525 million. The latter owned a plantation in Virginia consisting of 3,240ha of prime farmland, while his wife Martha inherited significant property from her father.
He is fourth of five children born to New York real estate developer Fred Trump and Mary MacLeod Trump. He is said to have inherited many of his father's characteristics but he rarely speaks about his family and his childhood growing up in Queens, New York. The few times he spoke about his father, it was only to the extent of calling him "very tough" and "very difficult".
It was at the military academy where the young Trump gained his ruthless streak. On the wall of the locker room of the baseball team at the academy was a quote from American football legend Vince Lombardi that particularly spoke to him: "Winning isn't everything, it's the only thing."
He suffered huge losses during the downturn, with the Trump Organisation depending on loans to stay afloat. His financial troubles also stemmed from mismanagement of three Atlantic City casinos, his ill-fated foray into the airline business and his ill-timed purchase of the Plaza Hotel in Manhattan. But the businessman made a comeback within a decade, reversing what was reported as a nearly US$1 billion deficit.
Mr Trump's emergence on the political scene may have felt a little like a bolt out of the blue, but the tycoon has actually had a three-decade long history of toying with the idea of a run, starting in 1987. Most had regarded the talk at the time as publicity stunt to drum up interest in his newly published book, "The Art of the Deal".
In his victory speech, Mr Trump praised his elder brother: "I also want to thank... my late brother Fred, great guy, fantastic guy." His brother, who was an airline pilot, started drinking when he went to college and became so addicted that he had to give up his job. He died of alcohol addiction in 1981 at the age of 43.