The song, which was the last one written for the album, was placed at the end of the album because it "marks a new beginning" for the band, which was the theme on the album and a theme in Lee's life. In the booklet of "The Open Door", she stated that her long-time friend and husband, Josh Hartzler, was the main inspiration for the song. In the booklet she wrote, "Josh, you are my muse. Nothing inspires me the way you do. Thank you for all my missing pieces. Thank you for your strength and love. Thank you for letting me see myself through your eyes, because only then could I know that I am good enough for you." One of the band's previous singles, "Bring Me to Life", was also written about Josh Hartzler. In an interview with VH1, Lee further revealed the inspiration behind the song, saying "I had gone through a lot of difficult things during the writing of the whole album, and by the end of it, I had stepped away from those bad situations. That's really hard. You have to be really brave and strong about it. After doing that, I felt so amazing. For the first time I felt like I could write a song based on how good I felt. I have never done that before ever. During another interview with "The Washington Post" she stated: