The group was founded by Ethan Todras-Whitehill, Miriam Stone, Josh Krafchin, Michelle Finocchi, and Matt Ewing to create ways for Democrats to volunteer in their nearest swing district.

[2] Swing Left focuses on training volunteers to register voters, phone bank, fundraise, and engage in door-to-door campaigning for Democratic candidates.

[3] Swing Left was the idea of Ethan Todras-Whitehill, a long-time Democrat who gained interest in starting the platform after being "flabbergasted and devastated" following the results of the 2016 United States presidential election.

[4] Todras-Whitehill initially decided to focus on gaining a Democratic majority in the House of Representatives which, at the time of Swing Left's founding, was controlled by the Republican Party, because it seemed "tangible".

Some notable donors of Swing Left include George Soros, Chris Sacca, and Tom Ford as well as organizations like Onward Together and Majority Forward.

[19] In 2019, Swing Left merged with Flippable, a group with a similar mission focused on flipping state legislatures from Republican to Democratic control.

[2] In 2018, Swing Left launched a campaign titled "The Last Weekend", where they partnered with Mandy Patinkin, Tracee Ellis Ross, Elizabeth Warren, Anna Wintour, and Kerry Washington, to encourage people to get out and vote through a series of videos.