The season follows Barry trying to stop Eva McCulloch and finding a way to locate his missing wife Iris West-Allen, and facing the consequences of the resurrection of the speed force and the ensuing Godspeed war.

The season is produced by Berlanti Productions, Warner Bros. Television, and DC Entertainment, with Eric Wallace serving as showrunner.

Grant Gustin stars as Barry, with principal cast members Candice Patton, Danielle Panabaker, Carlos Valdes, Danielle Nicolet, Efrat Dor, Tom Cavanagh, and Jesse L. Martin also returning from previous seasons, while Kayla Compton and Brandon McKnight were promoted to series regulars from their recurring and guest status in season six.

He conceded there may be a few small adjustments made based on how the pandemic would affect shooting, but said Eva McCulloch's story "is on a very specific trajectory that we want to honor and finish."

[42] While cast member Danielle Panabaker was initially written out of some episodes in the season to accommodate her maternity leave since she gave birth in April 2020, Wallace said there had been discussions about whether to write her back into them since the pandemic resulted in production delays, though he noted the rewriting process was "tricky".

Wallace also revealed they had a planned storyline for Dibny with another character that would have tied into the season's main villain.

[45] Main cast members Grant Gustin, Candice Patton, Danielle Panabaker, Carlos Valdes, Danielle Nicolet, Efrat Dor and Jesse L. Martin return as Barry Allen / The Flash, Iris West-Allen, Caitlin Snow / Frost, Cisco Ramon, Cecile Horton, Eva McCulloch, and Joe West.

[47][48] Hartley Sawyer was expected to return as Ralph Dibny / Elongated Man in the season, but on June 8, 2020, he was fired from the series after his past social media posts with racist and misogynistic references resurfaced in the wake of the George Floyd protests.

On December 1, 2020, David Ramsey was revealed to be reprising his Arrow role of John Diggle in the season.

[36] On January 13, 2021, Jon Cor was cast in a guest role as Mark Stevens / Chillblaine for the seventh season.

[50] In the same month, it was revealed that Jessica Parker Kennedy and John Wesley Shipp would be reprising their roles as Nora West-Allen / XS and Jay Garrick.