He founded Apollo with Leon Black and Marc Rowan in 1990 and later managed its daily operations until leaving in 2022 to focus on sports investments, done frequently in partnership with David Blitzer.

Harris sits on the board of the Mount Sinai Health System, Wharton, and HBS, is a member of the Council on Foreign Relations, and formerly served as treasurer of the Allen-Stevenson School.

[5] During summer vacations in 1983 and 1984, he managed operations of a lemonade stand business with locations at the National Zoo and Farragut North station in Washington, D.C.[3][8] Harris is a member of the Sigma Alpha Epsilon fraternity.

[3][4] Harris moved to New York City in 1986 to work at the Wall Street investment bank Drexel Burnham Lambert as a financial analyst in their mergers and acquisitions department.

Harris worked two months at Blackstone before leaving to establish the private equity firm Apollo Global Management later that year with former Drexel partners Leon Black and Marc Rowan.

[14] In May 2021, he announced he was stepping down from his day-to-day responsibilities at Apollo after being passed over as CEO for Marc Rowan, with his large personal focus on sports investments also reportedly becoming a source of tension within the company.

[15] The position had been made available after Leon Black announced he would be stepping down due to an investigation finding he had paid $158 million to convicted sex offender Jeffrey Epstein between 2012 and 2017 for advice on taxes and estate planning.

[15][17] Black included Harris in a civil racketeering lawsuit the same year, alleging that he led a group within Apollo attempting to tarnish his reputation after his ties to Epstein were reported.

[20] The firm offers direct lending and invests primarily in private equity, credit, and insurance companies, holding $22 billion in total assets under management as of May 2024[update].

[41][42] Harris would eventually agree to a suggestion by Silver to hire Jerry Colangelo, former owner of the Phoenix Suns, as team chairman in December 2015 with Hinkie stepping down in April 2016.

[47][48] He bought an 18% stake in the English football club Crystal Palace in December 2015, which is operated as a general partnership alongside Blitzer, Steve Parish, and John Textor.

[61] In 2023, Harris headed a group that purchased the NFL's Washington Commanders and Northwest Stadium from Daniel Snyder for $6.05 billion, the highest price ever paid for a sports team.

[62][63] The group has 20 limited partners, including Danaher and Glenstone founder Mitchell Rales, Hall of Fame basketball player and entrepreneur Magic Johnson, and D.C. venture capitalist Mark Ein.

[64][65] Harris and Johnson had bid on the NFL's Denver Broncos the previous year before it was sold to a group headed by Walmart executives Rob Walton and Greg Penner.

[69] In 2024, the pair sold their stake in the Steelers to Art Rooney II and Thomas Tull as NFL rules mandate a majority owner can not hold interest in another team.

[73][74] In March 2020, Harris and Blitzer committed to pay Prudential Center employees for any canceled events due to the outbreak of the COVID-19 pandemic, which saw the NBA and NHL suspend operations for much of the year.

[75] The same month, he introduced plans to reduce salaries of HBSE, 76ers, and Devils employees making over $100,000 by 20% but reversed the decision within a week after receiving public criticism, including an effort by 76ers player Joel Embiid to cover the losses of those affected.

He held his bar mitzvah at the Washington Hebrew Congregation in 1977 and spent three weeks working in Yahel, a Reform kibbutz in Israel, on a NFTY-sponsored trip in high school.

[81][82] Harris and fellow Chevy Chase native and businessman Mark Ein have been close friends since elementary school; they later attended Wharton and Harvard together and shared beach houses on Long Island during their time working on Wall Street.