Dr Choi has been Hong Kong's Under Secretary for Education since 2017, before assuming the post of Secretary for Education in 2022. Prior to joining the government, Dr Choi worked in the education field for nearly 30 years. She taught in secondary schools for more than a decade since 1988, before joining the Education Bureau where she was responsible for school-based curriculum development and language teaching support. In 2013, she took up the principalship of a secondary school. During the period, she took part in social and educational work, including the setting up of the Hong Kong Teachers Dream Fund. She also served on the Basic Law Promotion Steering Committee, the Fight Crime Committee and the Commission on Youth.