In the 1940s, influenced by Edgar Snow's book, Red Star Over China, Engst came to China as an expert of the United Nations. He traveled to Shanghai, Changsha and Yan'an. Touched by the Chinese Communists' confidence and positive attitude, he decided to stay with them and invited his girlfriend at the time, Joan Hinton, a nuclear physicist, to come to China with him. They later married in Yan'an, Shaanxi province.
In 1949, Engst was assigned a mission to assist in the establishment of the Sanbian pasture, a breeding stock farm located in today's Chengchuan town in Ordos.