John was born and raised in Sydney. After high school, John completed a Bachelor of Arts at Sydney University. At age 24 John moved to Adelaide to work as a secondary teacher. At Adelaide University he completed a Diploma of Education and a Bachelor of Laws. From 1986 to 1989 John was an Adviser to the Minister for Education, before being appointed as an official of the Australian Labor Party. From 1994 to 1997 he was Labor's State Secretary for South Australia. John was first elected to Parliament in 1997 as the member for the southern coastal electorate of Kaurna and appointed to the Shadow Cabinet. Following the election of the Labor Government in March 2002, John was appointed Minister for Environment and Conservation (until 23 March 2006), Minister for the River Murray (until 22 July 2004), Minister for the Southern Suburbs, Minister Assisting the Premier in the Arts, and Minister for Gambling (until 4 December 2002). On the 4 November 2005, John was appointed as Minister for Health. On 25 March 2010, John was appointed as Minister for Mental Health and Substance Abuse. In January this year John stood down from the Ministry following his announcement that he will not be standing at the election to be held in March 2014.