Between 2005 and 2010 he was the chief executive of the Newmarket Business Association.
In the 2010 Auckland Council elections Brewer was elected from the Orakei ward while standing as an Independent, winning by over 7,000 votes. He ran against Citizens & Ratepayers deputy leader Doug Armstrong. His decision to contest the election as a right wing independent, was labelled by a betrayal by C&R members while the result was considered a humiliation for C&R in its "traditional heartland".
In 2011 he decided not to contest the safe-National Party seat of Tāmaki, following the resignation of Allan Peachey, and also ruled out standing for the ACT Party. In the past he has been considered as a potential candidate for the Mayor of Auckland in 2013.
He was reelected unopposed to Council in 2013.
Brewer used to be married. He has one daughter and lives in Ellerslie with his wife Kate Brewer.
- Local Elections 2010 results elections2010.co.nz
- Brewer's stance dubbed 'betrayal' New Zealand Herald, 15 July 2010
- Cameron Brewer To Stand In Orakei Ward voxy.co.nz, 15 July 2010
- Left, right and centre - it's a council for all New Zealand Herald, 11 October 2010
- Challenger splits centre-right in Tory heartland New Zealand Herald, 23 August 2010
- Act plans for 'aggressive stance' with National New Zealand Herald, 5 May 2011
- National's plum candidacy is ripe for picking New Zealand Herald, 14 October 2011
- High-profile councillor cagey about bid for top job New Zealand Herald, 4 July 2011
- Len Brown destined to rule the roost in 'Bro-Town' The National Business Review, 13 December 2012