He wrote three textbooks and accompanying workbooks for high school students in Years 11 and 12 entitled Introducing Economics, published by Jacaranda-Wiley.
[7] In 2013, Collier nominated to contest Miranda once again in the by-election triggered by the resignation of his successor, Graham Annesley and won a surprise victory, returning to Parliament on the back of a 27 per cent swing- the largest swing ever recorded at a New South Wales by-election [8] In 2013, Collier withdrew his opposition to the F6 extension, saying he would support it if it was built as a tunnel under the Sutherland Shire.
[11] Collier decided to run for Sutherland Shire Council in September 2016 and became a councillor for B Ward with Labor gaining a 20 percent swing on the primary vote [12] He did not seek re-election in 2021.
[14] In September 2012, Collier was appointed by the NSW Government as a trustee of the newly created Rookwood General Cemetery Reserve Trust Board.
[3] Collier has written and published several poems including "Millennium Drought" for which he won the National Henry Lawson Literary Society Award for Free Verse in 2017[16][17] and "Anzac Day 2018: Let Us Also Remember.
The book details his successful grassroots campaign as an unknown, first-time Labor candidate to win the southern Sydney seat which had been held by the Liberal Party for 15 years.