He was educated at Gilles Plains High School and graduated from Flinders University[3] with a Bachelor of Science (Honours), majoring in Microbiology and Genetics.

[4] Following his graduation Hunter worked as a research assistant in the Department of Clinical Immunology at the Flinders Medical Centre, later serving as an advisor to the federal government and as Labor South Australian State Secretary.

[5] He used his maiden speech to outline his commitment to social justice issues and education as a force for progressive change, and attacked the push for the teaching of Intelligent Design as "fundamentalist dogma dressed up as science".

[9] Hunter was appointed to the Weatherill Ministry cabinet in October 2011 and served in a range of ministerial portfolios until the 2018 state election including communities and social inclusion, social housing, disabilities, youth, volunteers (2011 to 2013), sustainability, environment and conservation, water and the River Murray and climate change (2013 to 2018), and aboriginal affairs (between 2013 and 2015).

[11][12] Hunter and his partner of 20 years, Leith Semmens chose to travel to Spain to marry as Australian law did not recognise same-sex marriage at the time.

[13] Following an email campaign by Family First MLCs Andrew Evans and Dennis Hood the proposed amendment was defeated, and the Bill was referred back to the House of Assembly in its original form.

[21] Hunter, 52, married his long-term partner, Leith Semmens, 42, in Jun in the Province of Granada in southern Spain on 19 December 2012.