Most sources agree that, adjusting for inflation, John D. Rockefeller (d. 1937) was the richest American in history in terms of wealth vs. contemporary GDP. He amassed a fortune of more than $410 billion, adjusted to 2022.
There are various methods of comparing individuals' wealth across time, including using simple inflation-adjusted totals or calculating an individual's wealth as a share of contemporary gross domestic product (GDP). For example, economic blogger Scott Sumner noted in 2018 that Rockefeller was worth $1.4 billion when he died in 1937, which was about $24 billion in dollars adjusted to 2018. Meanwhile, Bill Gates in 1999 was worth nearly $150 billion in dollars adjusted to 2018.
The second-richest person in terms of wealth vs. contemporary GDP is disputed. Most sources list Andrew Carnegie, but others say Bill Gates, Cornelius Vanderbilt I, John Jacob Astor IV, or Henry Ford. Lower ranks are a matter of even bigger debate. Vanderbilt left a fortune worth $100 million upon his death in 1870 ($ today). As the United States became the foremost economic power in the world by the late 19th century, the wealthiest men in America were often also the wealthiest men in the world.
Fortune's wealthiest Americans (1957)
In 1957, Fortune magazine developed a list of the seventy-six wealthiest Americans, which was republished in many American newspapers. Jean Paul Getty, when asked his reaction to being named wealthiest American and whether he was really worth a billion dollars, said "You know, if you can count your money, you don't have a billion dollars" and then added, "But remember, a billion dollars isn't worth what it used to be."
The second category, covering the second to eighth richest individuals, included Andrew Mellon's son, daughter, niece, and nephew. Wealthiest Americans included a total of seven members of the Rockefeller family, five members of the Ford family, four members of the Du Pont family (and a non-family DuPont executive), and four General Motors executives.
$400,000,000 to $700,000,000
Ailsa Mellon Bruce, New York, New York; inherited wealth: Mellon Bank, Gulf Oil Company, Alcoa. Arthur Vining Davis, Miami, Florida; Alcoa, Florida real estate. H. L. Hunt, Dallas, Texas; independent oil operator. Paul Mellon, Upperville, Virginia; inherited wealth. Richard King Mellon, Pittsburgh, Pennsylvania; inherited wealth: Alcoa, Gulf Oil, Mellon Bank, etc. John D. Rockefeller Jr., New York; inherited wealth: Standard Oil Trust. Sarah Mellon, Pittsburgh; inherited wealth.
$200,000,000 to $400,000,000
Irénée du Pont, Wilmington, Delaware and Cuba; inherited wealth: E. I du Pont de Nemours & Co. William du Pont Jr., Wilmington; inherited wealth: E. I du Pont de Nemours & Co. Mrs. Frederick Guest, the former Amy Phipps, Palm Beach, Florida; inherited wealth from father Henry Phipps Jr., a Carnegie Steel executive. Howard Hughes, Los Angeles; inherited wealth: Hughes Tool Company. Joseph P. Kennedy, Boston, Massachusetts and New York; real estate. Daniel K. Ludwig, New York; National Bulk Carriers. Sid Richardson, Fort Worth, Texas; independent Oil operator. Alfred P. Sloan, Jr., New York; General Motors Corporation.