In May 1919 Yi Sin-ae joined the Hyeolseong Buinhoe women's group as an officer, raising funds for the Shanghai Provisional Government together with Jang Seon-hui, and later joined the Daedongdan, helping publish its newspaper Daedong Sinbo. In November that year, on the orders of its leader Jeon Hyeop, she helped arrange Prince Uichin Yi Gang's escape to Shanghai, but the plan was discovered in December and she was arrested along with four fellow members. She received the Order of Merit for National Foundation (Independence Medal) in 1963.