At the 2014 World Indoor Championships in Poland, Theisen captured silver in pentathlon with a personal best score of 4768, breaking her own national record. She next competed at the 2014 Commonwealth Games in Glasgow where she went on to win the gold medal in the women's heptathlon event ahead of compatriot Jessica Zelinka. After she said, "So this gold medal makes me really happy. I always said I don't think I would get choked up but I had to fight back a few tears [on the podium]. It's just representing your country and knowing everybody back home is happy and watching and supporting you. It feels really good."