Greg Weisman attributed the show's return to the existence of streaming services, particularly Netflix, where the show garnered high viewings. Executive producer Sam Register reportedly said that both Weisman and Brandon Vietti had created "the perfect binge-watching show five years too soon". Weisman posited that Young Justice might not have been cancelled if the model of binge-watching had been mainstream when the show was still on the air. Additionally, Brandon Vietti cited the power of social media, which grew exponentially since the show's cancellation, and the paramount role it played in allowing fans to have their voices heard.
Weisman claimed that he and Vietti were told about the show's return circa ten days before it was officially announced. However, he admitted to not being entirely surprised, because they had talked to Sam Register a year before and the chances of the show returning seemed higher. Vietti japed that "the time jump between season one and two worked so well in the story, [they] wanted to do it in real life".
Moving to a streaming platform
Regarding the changes in the writing process, Vietti observed that, on a streaming service, they are no longer restricted by the Broadcast Standards and Practices, as they were on Cartoon Network. He went on to say that, while they have no intention of changing the show dramatically, now they have more "creative room to progress into more adult themes and storylines", which reconciles with the nature of the show. However, he guaranteed that the show won't become a "swear" or a "gore fest".
For Greg Weisman, the biggest difference has been the lack of the three-act structure, because on a streaming service there are no commercial breaks in the episodes. He noted that despite still using it mostly by force of habit, this new paradigm sometimes changes the way they work.
Since production was announced, Warner Bros. has imposed an "info-embargo" on the show, which prohibits everyone involved from talking about it. The only public statement about the show came from Greg Weisman, when he revealed that the third season would "play off of stuff" from the previous seasons, as well as the companion comics.
On April 25, 2017 an official press release announced the title of the season, along with a plot summary:
"In the highly anticipated new season, the team faces its greatest challenge yet as it takes on meta-human trafficking and the terrifying threat it creates for a society caught in the crossfire of a genetic arms race spanning the globe and the galaxy."
On the same day, Brandon Vietti tweeted a pithier logline: "The Team battles meta-human trafficking to protect a society caught in the crossfire of a genetic arms race."
On July 21, 2017 at San Diego Comic-Con, Greg Weisman, Brandon Vietti and Phil Bourassa revealed new designs for old characters, and unveiled three new ones: Arrowette, Thirteen and Spoiler. They also announced that the season would comprise 26 episodes, ten of which had been recorded and another 12 were in progress. The final four episodes hadn't been written yet, but Weisman stated that they knew where they are going with them. Moreover, Brandon Vietti confirmed that there would be another time jump of unspecified length between seasons, because in order "to really delve into a character's story, you need to jump a little forward in time sometimes". Greg Weisman also offered some insight into the overall plot:
"Since the Reach in season two sort of revealed the Meta-Gene, everyone is getting into the act—first world nations, third world nations, rogue nations, corporations, aliens from outer space. Everyone wants to weaponize the human race and meta-human trafficking is the major thing that our characters are dealing with this season."
Without going into specifics, Weisman hinted that the season would feature some elements from the current DC ComicsRebirth run. Finally, in a post-panel interview, Weisman revealed that Bash Bashford, a very obscure character from old Superboy comics, would debut in season three.