York United FC

In December 2017, former Canadian international Jimmy Brennan stepped down as executive director of Aurora FC and announced his intentions to take a role within the Canadian Premier League. In March 2018, it was revealed that Brennan had been named executive vice-president of York Sports & Entertainment back in January. The following day, it was revealed that the company's president Preben Ganzhorn named himself as president of an unknown entity called York9 FC, believed to be a Canadian Premier League franchise.

On May 5, 2018, York Region was one of four groups accepted by the Canadian Soccer Association for professional club membership. Greenpark Group, headed by Carlo Baldassarra, was revealed as the owner of York9, with his son Mike as the chairman. Both Brennan and Ganzhorn were pictured at the Annual Meeting of the Members when the group was announced.

York9 FC was officially unveiled on May 10, 2018, as the first team to join the Canadian Premier League. As well as confirming their place in the league for the 2019 launch season, the club also revealed their crest, colours and branding. The club adopted the name York9 FC to represent the nine municipalities that make up York Region – Aurora, East Gwillimbury, Georgina, King, Markham, Newmarket, Richmond Hill, Vaughan, and Whitchurch-Stouffville. On July 27, 2018, York9 announced executive vice president of soccer operations Jimmy Brennan as the club's first head coach.

In August, York9 fielded a York Region Soccer Association Selects team to compete in the U17 International Soccer Cup held at York Lions Stadium. The team beat Juventus FC before losing to Toronto FC in the final.

The team has been called "Y9" and "The Nine Stripes" by the media and the league. York9's first match was the inaugural CPL match at Forge FC on April 27, 2019, launching the 905 Derby with a 1–1 draw, as Ryan Telfer scored the first goal in Canadian Premier League history.

To determine the Canadian Soccer Association's representative in the CONCACAF Champions League, York9 played in the 2019 Canadian Championship competing for the Voyageurs Cup. The team lost the quarterfinal to Montreal Impact after a 2–2 draw at home and a 1–0 loss at Montreal.

In early 2020 the team announced the departure of Preben Ganzhorn from the club. He was replaced by Angus McNab, initially as a management consultant and later as the team's President, GM, and CEO.

York9 was expected to begin their second season in the Canadian Premier League in April 2020 but the season was delayed by the COVID-19 pandemic. During the postponement, the club sold young midfielder Emilio Estevez to Dutch Eredivisie side ADO Den Haag, the first CPL player to be sold to a European top flight.

On December 11, 2020, the club was rebranded as York United FC, adopting a new crest and colour scheme along with the name change. While the original club name exclusively targeted York Region, the new branding also represents the City of Toronto. In their first season as York United FC, the club finished 4th in the 2021 Canadian Premier League season. They were eliminated from the playoffs after a 3–1 loss to Forge FC. Following the season, head coach Jim Brennan's tenure at the club ended after it was announced November 23, 2021, that his contract would not be extended. He was replaced by Martin Nash on December 21, 2021.

During the 2023 season, it was announced that the club was sold from the Baldassarra family to the Canadian Soccer Business with plans to transfer the club to new ownership. Angus McNab stepped down from his role as president, CEO, and general manager following the season on November 3, 2023. On November 30, 2023, the Canadian Premier League announced that Mexican-based Game Plan Sports Group had purchased York United with immediate effect. The ownership group is led by brothers Eduardo, Ricardo and Miguel Pasquel, who each took roles in the day-to-day operations of the club, respectively, as chief executive officer, president and general manager, and chief commercial officer.

On May 21, 2024, manager Martin Nash was relieved of his head coaching duties and replaced by Mauro Eustáquio on an interim basis. On June 4, 2024, York United FC announced Benjamín Mora as their new head coach.