Born and raised in Brisbane, Brewer graduated from Forest Lake College in 2008. After moving to Melbourne, Brewer shared a flat with fellow Neighbours co-star Margot Robbie.
A week after graduating from her school, Brewer arrived in Melbourne to look for acting work. While she was in the city, Brewer successfully auditioned for the ongoing role of Kate Ramsay in the long-running soap opera Neighbours. The actress relocated to Melbourne for filming and she made her debut as Kate on 15 May 2009. The following year, Brewer was nominated for the Most Popular New Female TalentLogie Award. In July 2013, Brewer celebrated filming 1000 episodes.