The 2012 Summer Olympics in London was Ki's first appearance at the Olympics. She began the preliminary 72-arrow ranking round with a score of 671 points from a maximum of 720, tying her at the top of the standings for the women's individual event with teammate Lee Sung-jin and Chinese Taipei's Tan Ya-ting. Ki was however ranked first and awarded the number one seed for the elimination rounds on countback after landing a higher number of arrows in the central ring of the target. With a combined score of 1,993 points, Ki, Lee, and Choi Hyeon-ju also secured the number one seed for South Korea in the women's team competition.