Steven Terner Mnuchin (/məˈnuːʃɪn/ mə-NOO-shin; born December 21, 1962) is an American investment banker and film producer who served as the 77th United States secretary of the treasury as part of the first cabinet of Donald Trump from 2017 to 2021. Serving for nearly a full presidential term, Mnuchin was one of the few high-profile members of Trump's cabinet whom the president did not dismiss during his first term.

Mnuchin was born in New York City. Upon graduating from Yale University in 1985, Mnuchin joined the investment bank Goldman Sachs where his father, Robert Mnuchin, was a general partner. Mnuchin worked at Goldman Sachs for 17 years, eventually becoming its chief information officer. After he left Goldman Sachs in 2002, he worked for and founded several hedge funds and launched Dune Entertainment, a film production company that financed several films for 20th Century Fox. He later served on the boards of Kmart and Sears Holdings. During the 2008 financial crisis, he bought failed residential bank Indymac, which he reorganized as OneWest Bank and resold, becoming embroiled in lawsuits over questionable foreclosures.

Mnuchin joined Trump's presidential campaign in 2016, and was named National Finance Chairman for the campaign. On February 13, 2017, Mnuchin was confirmed by the U.S. Senate as Secretary of the Treasury by a vote of 53–47. As Secretary of the Treasury, Mnuchin supported the Trump tax cuts and the tax reform of 2017, and advocated reducing personal and corporate tax rates. In regard to regulatory policy, Mnuchin supported President Trump’s partial repeal of the Dodd–Frank Act, citing the complexity of the legislation.

Steven Mnuchin was born on December 21, 1962, in New York City, the second-youngest son in his family. Mnuchin's family is Jewish. He is the son of Robert E. Mnuchin of Washington, Connecticut, and Elaine Terner Cooper of New York. Robert Mnuchin was a partner at Goldman Sachs in charge of equity trading and a member of the management committee. He is also the founder of an art gallery in New York City, the Mnuchin Gallery. Mnuchin's great-grandfather, Aaron Mnuchin, a Russian-born diamond dealer who later resided in Belgium, emigrated to the U.S. in 1916.

Mnuchin attended Riverdale Country School in New York City. He graduated from Yale University in 1985 with a bachelor's degree in economics. At Yale, Mnuchin was publisher of the Yale Daily News, and was also initiated into Skull and Bones in 1985. While a student at Yale, Mnuchin drove a Porsche and lived at New Haven's Taft Hotel.

Mnuchin's first job was as a trainee at investment bank Salomon Brothers in the early 1980s, while still studying at Yale.

Mnuchin graduated from Yale in 1985 and started working for Goldman Sachs, where his father had been employed since 1957. Mnuchin started in the mortgage department, and became a partner at Goldman in 1994. Until he left the company in 2002, Mnuchin held the following positions as a partner:

Mnuchin left Goldman Sachs in 2002 after 17 years of employment, with an estimated $46 million of company stock and $12.6 million in compensation that he received in the months prior to his departure.