Derwin sold his legal practice in 1992 to become Chief Executive Officer of Surf Life Saving Australia, a position that he held until 1996. Derwin was Chief Executive Officer of the Australian Paralympic Federation for the period 1997 to 1999. During this period, the organisation changed its name to the Australian Paralympic Committee and prepared Australian athletes for the 2000 Sydney Paralympics. Between 1999 and 2008, he was Chief Executive Officer of Basketball Australia. Whilst undertaking this role, Derwin managed the unification of Basketball Australia with National Basketball League and Women's National Basketball League. He then moved to the Sunshine Coast, Queensland in 2009 and has become involved in sport administration in this region. In 2011, he became Chairman of the Sunshine Coast Sports Federation and Chairman of the Bid Committee 2016 Australian Surf Lifesaving Championships, Sunshine Coast. After a period as Chair of Basketball Queensland, he became Chair of Basketball Australia in 2012.