The 23-year-old former soap actress is part of a cast refresh, which will also include Jack Roth (The Cafe), Nikesh Patel and Gemma Chan (Secret Diary of a Call Girl) joining the show.
Hugo Speer will return as Warren Bettany, the owner of Bedlam Heights, while Charlotte Salt is back as his daughter Kate.
Turner is cast as paramedic Ellie, who is struggling with her special ability to see ghosts. Since leaving EastEnders last Christmas, the actress's TV roles have included turns in BBC Three's Being Human and Frankenstein - Live.
"I am really excited about taking part in the second series of Bedlam," said Turner.
"It's a great story with brilliant writing and a fantastic cast. Ellie is a really interesting and conflicted character. I'm looking forward to playing her and seeing where the story takes her."
Sky's Anne Mensah commented: "We have huge ambitions for Bedlam. The show is a unique combination of engaging relationship drama and real scares. Our fantastic cast are delivering wonderfully on the emotional material and our great production team seem determined to terrify the audience. It's a fantastic mix."
Bedlam is written and created by Neil Jones, David Allison and Chris Parker.
The second series will launch on Sky Living in spring 2012.