Between 1987 and 1991, Chan served as judge in
District Courts, having been appointed a District Judge on 9 November 1987. In 1991, he was appointed Deputy
Registrar of the
Supreme Court. In 1992, he began serving as a Judge in the
Court of First Instance of the
High Court of Hong Kong. Chan was appointed the first
Chief Judge of the High Court in 1997, when British colonial rule in Hong Kong ended and China resumed its sovereignty over the region. He thus became the first locally educated judge to hold that position. In 2000, he was appointed a Permanent Judge of the
Court of Final Appeal (Hong Kong's
court of last resort). He retired in 2013 and was succeeded by
Joseph Fok. He continues to serve as a Non-Permanent Judge of the Court. During his time on the bench, Chan contributed significantly towards the development of a bilingual legal system, and served on various judicial committees advocating the greater use of Chinese in judicial proceedings and the translation of English judgments. In February 2021, Chan claimed that there is no absolute
separation of powers in Hong Kong, and that "It is more accurate to call it a division of authority." In May 2023, the
Congressional-Executive Commission on China (CECC) of the
United States Congress suggested the United States government imposing sanctions on Chan to counter the erosion of democratic freedoms in Hong Kong over his handling of
Jimmy Lai's
national security law case. ==Extra-judicial Life==