In June 2011, Syfy announced that they would be producing a television series which was being developed by Rockne S. O'Bannon and would be produced by Universal Cable Productions. It was also announced that the TV series would be connected to a video game being produced by Trion Worlds. It was later confirmed that Syfy had ordered thirteen episodes for the show's first season, which would premiere in either late 2012 or the summer of 2013. In July 2012, the network announced that the series and game would debut in April 2013.

Production of the first season began in April 2012 in Toronto.

On May 10, 2013, Syfy renewed Defiance for a 13-episode second season to air starting in June 2014, with production from August to December 2013.

On October 16, 2015, the show was cancelled by Syfy citing financial reasons after having completed its third season. However, the companion video game continues to be supported; on March 1, 2016, Trion Worlds announced a major update for the game, promoted as season four of the show. They also stated they had no plans of making a sequel, instead they will continue to update the game with new content. The new version, named "Defiance 2050", will come out in 2018 for PC, Xbox One, and PS4.

Defiance received a "fresh" rating from Rotten Tomatoes of 61% for the first season, a score that rose to 76% over the three seasons. The first season of Defiance was rated "mixed or average" by Metacritic, with a 57% rating according to 17 reviews. Maureen Ryan of The Huffington Post called it "a smart, well-crafted TV show with a good cast and an adventurous flavor" and added "it's also indisputably science fiction, which is a relief," saying that she felt too many science fiction shows were "watered-down ... genre-lite dramas". She also praised the casting, performances and the production design. Ellen Gray of the Philadelphia Daily News noted that "the TV show may not break new ground ... but it does stand on its own as a watchable sci-fi series, with a Wild West vibe mixed with a bit of "Farscape-meets-West Side Story." Conversely, David Hinckley of the New York Daily News gave it one star out of five and found it to be "incomprehensible", but said "if you’re a sci-fi fan for whom this stuff can never be too complex, have at it." Other reviewers gave Defiance average reviews and noted its similarity to previous television series, while at the same time praising its "breathtaking" landscapes and "impressively rendered" monsters; its "intriguing" cast and setting; its digital effects and performances; and its mythology and "interesting" story.