[2] As CEO of Monumental Sports, he has used the threat of leaving Washington D.C. to demand that District of Columbia taxpayers subsidize the operations of his D.C.-based teams.

[3] Leonsis was born on January 8, 1957, in the Brooklyn borough of New York City, to a family of working-class Greek immigrant grandparents, who were mill workers,[4][5] and parents who worked as a waiter and a secretary.

[4][9][10] After graduating from college, he moved back to his parents' home in Lowell and began working for Wang Laboratories as a corporate communications manager and Harris Corp. as a marketing executive.

[29] In the early years of his ownership, the Capitals went on to win back-to-back Southeast Division titles in 2000 and 2001, but lost in the first round of the playoffs to the Pittsburgh Penguins.

[31] He was involved in a physical altercation with a fan, who led a mocking chant of Leonsis during the game and hoisted a sign chiding him.

[32] After the incident, Leonsis personally called the fan to apologize for his actions and invited him and his family to watch a game in the owner's box.

[39][40] In 2011, after raising ticket prices for the fourth consecutive year while shrinking the size of beers sold at the Verizon Center, he earned the nickname "Leon$i$".

[41] In 2001, Leonsis claimed to have written a computer program that prevented Pittsburgh Penguins fans (the Capitals first-round opponent) from purchasing tickets online.

[44] Critics said the signage would make the arena more garish and cheapen DC's Chinatown, Leonsis said it was necessary to raise an additional $20 to 30 million in annual revenue, and a sports expert explained that "an owner saddled with underperforming teams is under greater pressure to find income sources.

Leonsis became the majority owner of the Washington Wizards in June 2010, inheriting a team that had 26 wins and 56 losses during the previous season.

[48] Leonsis was initially believed to have taken a fan-centric approach to running the franchise, thought to be listening and responding to the concerns of Wizards supporters through his email and personal website.

"[50] In May 2011, the Wizards unveiled a red, white and blue color scheme, along with uniforms reminiscent of those worn by the team under their former name, the Bullets, when they won the NBA Championship in 1978.

[51] Additionally, he had taken under consideration restoring the Bullets name to the franchise,[52] though critics said that this would "send the wrong message" about gun violence in Washington.

[53] Leonsis was chairman of the NBA's 2014 media committee that negotiated a nine-year expanded partnership with Turner Broadcasting and The Walt Disney Company.

[55] Leonsis purchased the rights to the Washington Mystics, a Women's National Basketball Association team, around the same time he took over the Wizards.

[56] On March 10, 2016, Leonsis announced that he was purchasing an expansion franchise in the Arena Football League (AFL) to play at the Verizon Center beginning in 2017.

Leonsis was the founder, chairman and largest shareholder of the defunct SnagFilms, a content and technology company with a full-service video streaming platform.

The film was narrated by actor Colin Farrell and featured residents of Afghanistan; Kenya; Dublin, Ireland; Charlotte, North Carolina; Madrid; and Saint Petersburg.

[64] A third documentary, A Fighting Chance, tells the story of Kyle Maynard, who became a nationally ranked wrestler, motivational speaker, and bestselling author, despite being born without arms or legs.

[80] Leonsis has authored a number of books, including Blue Magic: The People, Power and Politics Behind the IBM PC and The Business of Happiness: 6 Secrets to Extraordinary Success in Work and Life.