Rix was born on the Central Coast of New South Wales. She participated in numerous amateur musical theatre productions from the age of 4. She began to perform throughout Sydney as the lead singer of a pop band at the age of 18. Rix then moved to Melbourne at the age of 21 to devote herself to musical theatre and was cast in a number of commercial projects.
Rix moved to Osaka, Japan after being cast as the Bride of Frankenstein in The Monster Rock and Roll Show at Universal Studios Japan. In July 2006, she was cast as Elphaba in the USJ mini version of the Broadway musical Wicked, which required her to perform parts of the show in Japanese. Throughout the audition process, she met and performed for Stephen Schwartz, Winnie Holzman and Marc Platt. She performed in this role for a year before returning to Melbourne.
Rix was cast as the standby for Elphaba in the Australian premiere of Wicked which opened in Melbourne on 12 July 2008 and ran through 9 August 2009. The show was then transferred to Sydney, opening on 12 September 2009. Due to the illness of Amanda Harrison, Rix had many opportunities to perform the role of Elphaba, and on 9 February 2010, after an extended leave of absence, Harrison announced that she would not be returning to the show. The role was then offered to Rix, who continued to share it with Australian theatre actress Pippa Grandison. They starred alongside Lucy Durack in the role of Glinda. Rix generally performed in four of eight shows a week, with the remaining four played by Grandison and later, Patrice Tipoki.
Rix continued to be the first billed Elphaba, featuring on displays outside the theatre and appearing at most events and press interviews. These included the 2008 Carols by Candlelight, Melbourne's Federation Square and Town Hall, 2009 Australian Ethnic Business Awards, 2009 QANTAS Business Awards, AFL pre-match entertainment performances, the ANZ Rob Guest Endowment Fund Concert, the Kerri-Anne Kennerley morning TV show, Sydney's Carols In The Domain 2009, the 2010 Telethon, and the 2010 Carols by Candlelight. Wicked closed in Sydney on 26 September 2010, with Rix playing Elphaba.
Rix again played the role of Elphaba on the show's first Australian Tour, which, after delays due to flooding, began in Brisbane on 25 January 2011.
In 2011, Rix was nominated for a Helpmann Award for "Best Female Actor in a Musical" for her portrayal as Elphaba in Wicked.
Rix played Elphaba again on the Asian tour of Wicked, which began in Singapore from 7 December 2011. After a four-month engagement there, the tour visited Seoul. Previous Australian understudy Suzie Mathers took over the role of Glinda full-time at the start of the Asian tour.
Rix reprised her role as Elphaba in Auckland, New Zealand as of 21 September 2013 at the Auckland Civic Theatre. After Auckland she traveled to Manila, Philippines to perform there. Rix continued to play the role for the 10th Anniversary return tour in Australia, performing in Melbourne, Sydney, Brisbane and Perth. During the tour, she reached a milestone by performing the role of Elphaba for 1000th time in October 2014.
It was announced mid 2015 that Rix would play the role Lucy, in the Australian production of Jekyll & Hyde the musical, however the production has been postponed indefinitely. Rix is currently playing the role of Molly Jensen in the Australian tour of Ghost the Musical.
Rix married Josh Rix on 2 February 2009, and they live in Melbourne.