In 2001, he was appointed managing director of Cavendish Publishing, with a 30-percent stake in the company.[3] By 2003, it was the largest independent law publisher in the United Kingdom.[2]
In 2006, Leong sold Cavendish Publishing to Taylor & Francis.[4] He left Taylor & Francis in 2007 to join One Charter, a private jet business, as a non-executive director.[4]
Formerly the Chair of Chinese for Labour,[5][6] in October 2022, it was announced that he would receive a life peerage in the 2022 Special Honours.[7] On 31 October 2022, he was created Baron Leong, of Chilton in the County of Oxfordshire and of Camden Town in the London Borough of Camden.[8][9]