[1] The season follows Barry dealing with the consequences of his future daughter's time traveling, while confronting a new foe in Orlin Dwyer, also known as Cicada.

The season was produced by Berlanti Productions, Warner Bros. Television, and DC Entertainment, with Todd Helbing serving as showrunner.

Grant Gustin stars as Barry, with principal cast members Candice Patton, Danielle Panabaker, Carlos Valdes, Tom Cavanagh, and Jesse L. Martin also returning from previous seasons, while Hartley Sawyer, Danielle Nicolet, and Jessica Parker Kennedy were promoted to series regulars from their recurring status in season four.

They are joined by new cast member Chris Klein while former series regular Keiynan Lonsdale makes a guest appearance.

On Earth-1, the stranger presents the book to Arkham Asylum psychiatrist Dr. John Deegan and instructs him to rewrite reality as he sees fit.

Barry and Oliver use each other's abilities to escape and convince a reluctant Iris to allow them to flee to Earth-38 to enlist the help of Kara Danvers / Supergirl and her cousin, Clark Kent / Superman.

At the Television Critics Association winter press tour in January 2018, The CW president Mark Pedowitz said he was "optimistic" and "confident" about The Flash and the other Arrowverse shows returning next season, but added that it was too soon to announce anything just yet.

He is not a cult leader as he is in the comics, but is portrayed as a "grizzled, blue-collar everyman whose family has been torn apart by metahumans" and who views the rise of metas as an epidemic, and seeks to exterminate them one by one.

[71][72] Main cast members Grant Gustin, Candice Patton, Danielle Panabaker, Carlos Valdes and Jesse L. Martin return from previous seasons as Barry Allen / Flash, Iris West, Caitlin Snow / Killer Frost, Cisco Ramon / Vibe and Joe West, respectively.

[77] Helbing credited the decision of having Cavanagh play Thawne-as-Wells over Matt Letscher as simply Thawne to making sense in a "weird, time travel way" and be applicable to the season's theme of "legacy".

[92] Due to Martin's injury, the majority of his scenes in the first half of the season were shot depicting Joe seated.

[94] In May 2018, Arrow star Stephen Amell announced at The CW upfronts that the next Arrowverse crossover would feature Batwoman and Gotham City.

[73] Starting on September 14, 2018, several billboards advertising Ralph Dibny as a private investigator were seen around Vancouver, the city where the show is filmed.

The website's consensus reads, "The Flash's fifth season maintains the show's high standard for compelling visuals, chilling villains, and well-scripted moments of humor, but also turns a more focused gaze on the role of family dynamics amongst the increasingly complex characters.

Club further praised Kennedy's performance, and gave the premiere a "B+" and "B" grade, respectively, with Agard concluding, "The Flash is now in its fifth season, which means the show's accumulated history is one of its greatest strengths it has.