 Specialised in Human Resources studies, Shamsul is a former Football Association of Singapore (FAS) referee retired in 2007.Recognised for his experience as referee instructor and referee assessor at FIFA and AFC level, Shamsul Maidin was appointed as part of the instructors' team of the 2012 Olympic Games in London and the 2010 FIFA World Cup in South Africa.Other highlights of his career include the 2004, 2000 and 1996 AFC Asian Cup editions, as well as the 2003 and 2001 FIFA World Youth Championships.