Her professional career began in 2005 in Grease: The Arena Spectacular, playing the role of Patti Simcox. She then went on to reprise the role in the UK. In both productions she understudied Sandy's role. On returning to Australia, she played the role of April in Gale Edwards's 2007 production of Company. In 2008 she received the Sydney Theatre Award for Best Newcomer.
She has also starred in Britney Spears: The Cabaret which began at the 2009 Adelaide Cabaret Festival and later in Sydney and Melbourne. She starred in The Drowsy Chaperone for Melbourne Theatre Company in the role of Janet van de Graaf, for which she was a nominated for a Helpmann Award for Best Female Actor in a Musical.
She played the title role in The Production Company's Sugar, for which she was a Green Room Award nominee for Best Actress, and played the lead role of Kira in the musical Xanadu. More recently she played the role of Erma in Anything Goes.
She played the role of Lucy in Bryant and Frank's Australian musical Once We Lived Here, for which she was a Green Room Award nominee for Best Supporting Actress. Other credits include Maisy in The Boy Friend, as well as roles in 42nd Street, The Rocky Horror Show, Starting Here, Starting Now and The Shakespeare Review.
She also appeared in the 2010 film I Love You Too.
Whelan-Browne appeared on an episode of Spicks and Specks in June 2011 on ABC Television. She also has appeared on The Circle, Winners & Losers as Kylie McDonald and Offspring as Jenny. Other TV credits include Leila in Miss Fisher's Murder Mysteries and Katerina in Conspiracy 365.
She played Gwendolen in The Importance of Being Earnest for the Melbourne Theatre Company. Her one-woman show Britney Spears: The Cabaret has earned her rave reviews and sell out seasons since its conception at the 2009 Adelaide Cabaret Festival.
She played Philia in the Melbourne season of A Funny Thing Happened on the Way to the Forum opposite her mentor Geoffrey Rush for which she was nominated for a Green Room Award for Best Supporting Actress.
Whelan-Browne starred in Shane Warne: The Musical as Elizabeth Hurley at the 2013 Adelaide Cabaret Festival. She also played Lina Lamont in Singing in the Rain for The Production Company. She hosted the Helpmann Awards alongside Eddie Perfect. On TV, she had an arc in Network Ten's drama series Wonderland as Kristen.
in 2014 she was part of the 40th anniversary tour of The Rocky Horror Show playing the role of Janet Weiss.
In 2015 she played the role of Olivia Newton John in the miniseries Peter Allen: Not the Boy Next Door on Channel 7. She also made a cameo in House Husbands as an inappropriate dance teacher. She starred in a new one woman show Show People written by the makers of Britney Spears: The Cabaret and it played at the 2015 Adelaide Cabaret Festival. She played the role of Eileen Evergreen in The Production Company's Nice Work If You Can Get It and Jerry's Girls.
She is currently filming The Wrong Girl for Network 10 and her first feature film Spin Out was released in September. Whelan-Browne will appear in Melbourne Theatre Company's production of The Odd Couple from November 2016, and as Billie Dawn in their 2017 production of Born Yesterday.
- "Company B sweeps Sydney Theatre Awards". abc.net.au. Retrieved 21 May 2011.
- "Britney Spears: The Cabaret (Luckiest Productions)".
- Usher, Robin (27 September 2010). "Sweet Sugar likes it hotter". The Age. Retrieved 8 December 2011.
- "Natalie front-runner for Xanadu". Herald Sun. Retrieved 21 May 2011.
- Litson, Jo (26 February 2011). "She can do magic". The Australian. Retrieved 8 December 2011.
- "2009 Green Room Award Nominations Announced". Australian Stage. 16 February 2010. Retrieved 22 January 2017.
- "Spicks and Specks, 1 June 2011".
- "Winners & Losers: World's Collide — Episode 4". throng.com.au.
- "Newlyweds Christie Whelan and Rohan Browne to perform together in The Producers". heraldsun.com.au.
- "The Odd Couple - Melbourne Theatre Company". Melbourne Theatre Company. Retrieved 2016-10-17.
- "Born Yesterday - Melbourne Theatre Company". Melbourne Theatre Company. Retrieved 2016-10-17.