Season Two of Supergirl brought with it many changes, not the least of which was a change in network. Shortly after the season one finale, CBS announced that it would be discontinuing its production on Supergirl, likely due to declining ratings. Berlanti Productions was only too quick to sell the show to the network's partner, the CW Network, which was not only co-owned by DC Comics' parent company, Warner Bros. Television, but was already the home to several DC licensed works including Arrow, The Flash, Legends of Tomorrow and iZombie (the first three of which all take place in the same continuity. Supergirl already proved itself a nice fit for the DC Television Universe with the season one episode, "Worlds Finest", which guest-starred The Flash 's Grant Gustin, so it only made sense that the series would find a new home at the CW. To mitigate production costs, the show intended on relocating from filming in Los Angeles to Vancouver, Canada.
Season two saw some new faces as well, but familiar ones (in one form or another). Supergirl's older and more infamous cousin Superman made cameo appearances in season one, but was always obscured from view, offering up glimpses of a cape or a boot and the occasional behind-the-scenes appearance via text conversations between Clark Kent and Kara Danvers. But now, Superman would have a face. Former Teen Wolf actor Tyler Hoechlin was cast to play the Man of Steel for season two. In terms of iconic casting, Supergirl already paid fan service to DC's history with the casting of Supergirl film star Helen Slater as Eliza Danvers, and former Lois & Clark: The New Adventures of Superman star Dean Cain as Jeremiah Danvers. It was announced that actress Lynda Carter, who became one of the biggest names of the small screen in the 1970s for her portrayal of Wonder Woman was cast to play the President of the United States on Supergirl. Once again, Carter got the chance to represent the red, white and blue in an important and unforgettable way.
It was announced that Tyler Hoechlin would play the role of Superman in the first two episodes of the season two premiere. Showrunners Greg Berlanti and Andrew Kreisberg were very excited about adding Hoechlin to the series, stating that they had wanted to work with the actor for some time. 
It was always Greg Berlanti's intention to bring Lynda Carter onto Supergirl, and there had already been several references made in season one to the President of the United States being a woman. Carter's schedule did not allow for her inclusion in season one, and it wasn't until production of season two was a lock that they officially announced that she would be making appearances on the series. 
Because of the change in production venue from Los Angeles to Vancouver, series regular Calista Flockhart went from being a regularly billed character to a recurring character on season two. Executive producer Andrew Kreisberg said. "We are so excited Calista has agreed to continue on the show when she can. We and the audience love to see her on screen."