London City Lionesses Women

On 13 May 2019, a statement was released by Millwall F.C. announcing that the board of directors and senior management at the team's official women's affiliate, Millwall Lionesses, had declared their intentions to split from the club, becoming an independent entity and operating under a new name. The breakaway was already agreed in principle by the FA. The transfer of Millwall's Championship licence was officially approved by the FA on 29 June 2019. The newly-independent club's operations were funded from 2019 by blockchain entrepreneur Anthony Culligan and his wife Diane, with Diane Culligan serving as chairwoman and running the club's operations.

The start of the 2022-23 season saw considerable optimism from club management after England's triumph in the 2022 Euros drove an increase in club season-ticket sales. The Lionesses hit challenges later that season, however, with their manager Melissa Phillips resigning in January 2023 to take an assistant manager role with Angel City FC, despite the club sitting in first place. In June 2023, all 20 of the club's players sent a collective message to owner Diane Culligan asking her to sell the club or raise additional investment, citing financial instability, a lack of players signed for the upcoming season and the lack of a permanent manager. On 15 December 2023, the Culligans sold the club to entrepreneur and Washington Spirit owner Michele Kang for an undisclosed price.

On 27 June 2024 Kang announced the signing of Kosovare Asllani, captain of the Sweden national side, and the appointment of Jocelyn Prêcheur, formerly of Paris St Germain, as the new manager. The signing of Asllani, who has previously played for Manchester City, Real Madrid and AC Milan, was described as "a statement of intent that will have raised eyebrows around the global women's game." It was also announced that the club would move from Princes Park (Dartford) to Hayes Lane in Bromley under a ground-sharing agreement with Bromley F.C.

On 27 July 2024, Kang announced the launch of Kynisca Sports International Ltd., a worldwide multi-team organisation to provide the infrastructure to support the development of London City Lionesses alongside sister clubs Washington Spirit and Olympique Lyonnais Féminin. Under Kynisca, it was intended that each club would retain its own established identity, but that there would be a shared, central capability for aspects such as performance science and technology, data analytics, global scouting, and sporting staff development. ​