The cast of the show announced the renewal with a Twitter video on Saturday morning.
The sci-fi series from the Wachowskis and J. Michael Straczynski originally debuted in early June to mixed reviews.
Straczynski had expressed his hopes for a second season at the TCA Summer Press Tour in late July.
“The way that the Wachowskis and I tend to work — we created the show together and we are running the show together — we are long-thinking people,” Straczynski said. “We look down the road and we say to ourselves, ‘Where is this going to go?’ … Season one is like an origin story and season two has some particular arc, and we figure it out from there. But to spoil that here would not be the best interest of the surprise at the end.”