Chui is a trader by occupation and participated in the 79-day Occupy sit-ins in 2014. Inspired by the Occupy movement, he formed a group called “umbrella fathers and mothers” with other protesters and ran in the 2015 Hong Kong district council elections against long-term incumbent Christopher Chung Shu-kun, who was also the member of the Legislative Council of Hong Kong for the Democratic Alliance for the Betterment and Progress of Hong Kong, the largest Beijing-loyalist party in Hong Kong, in Yue Wan, his home of more than two decades. He remained unknown to the media until he beat Chung by 2,017 votes to 1,826, a "miracle" portrayed by the media. Chui successfully defended his seat in the