Fan was a contract artiste under the Hong Kong television station TVB throughout the 1990s, and he starred in some television dramas like Demi-Gods and Semi-Devils (1997) and Young Hero Fang Shiyu (1999). He left TVB later and worked on some Taiwanese and mainland Chinese television series before focusing on films; most of the movies he acted in during this period are not very well-known internationally.
After completing his studies, Fan returned to the film industry and made his debut as a leading actor in Stanley Tong's The Stone Age Warriors (1991). In 1992, at the age of 18, Fan rose to fame for portraying the titular character in Riki-Oh: The Story of Ricky, a Hong Kong film based on the manga Riki-Oh.
Fan's most recognisable role in more recent times is "Jin Shanzhao", the tough Northern martial Artist in the 2008 film Ip Man, which starred Donnie Yen as Wing Chun grandmaster Ip Man. Fan's performance in Ip Man earned him a nomination for Best Supporting Actor at the 28th Hong Kong Film Awards in 2009. He reprised his role as Jin Shanzhao in Ip Man 2, a 2010 sequel to Ip Man. He played a new character in The Legend Is Born – Ip Man (2010), another movie about Yip Man that is unrelated to Ip Man and Ip Man 2.
Louis has two children from a previous relationship. In 2012, he began dating Actress and singer JJ Jia. After announcing their engagement in November, the two were married on January 1, 2016 in a very private ceremony in Hong Kong.