Xie made her acting debut when she was cast as a nurse in the local hit drama series, Growing Up. Her convincing acting landed her one of her most recognisable roles in the sitcom, My Genie. In 2001, she won "Best Newcomer Award" at Mediacorp's Star Awards after just over a year in show business, after overcoming much criticism about her fake American accent.^{[citation needed]}

Of late, Xie has become known for her talents as a bilingual variety show hostess, in particular of the long-running series, City Beat. She has since hosted other variety shows, such as the photography-based "Say Cheez" for Channel 8, and introducing celebrities' favourite hawker foods in "Coffee Talk and Hawker Woks" for Channel 5. Recently she and actor Ben Yeo also hosted the travel show "Weekend Escapade".

In 2004, Xie made the news when she had to run with Jeanette Aw, Xiao Qiao and Felicia Chin, in bikinis, along the crowded Orchard Road for the drama series "The Champion". She later admitted in an interview that she wore another bikini top underneath, to prevent accidental exposure. That scene alone earned Fiona the nickname of "Boing Boing".

Besides her work as host and actress, Xie has also endorsed numerous products because of her popularity with the mainstream population. These range from Marigold juices to Osim massage products.

In 2005, Fiona was voted as sexiest woman for the "FHM Top 100 Sexiest Women Singapore" list, even though she had never posed for FHM before. She continued to be ranked among the Top 10 for the FHM lists in the next 3 years.

In 2006, Fiona attempted her first villain role as a spoilt diamond heiress in the drama series An Enchanted Life, starring alongside Yvonne Lim and Pierre Png.

In 2007, Fiona Xie took part in the second season of the Singapore Edition of Deal or No Deal, where her winnings would go to a selected charity organisation. The episode aired on November 22 2007.

Fiona appeared in her second film project and first ever international film, "Rule #1", directed by local filmmaker Kelvin Tong. The film starred HK actors Ekin Cheng and Shawn Yue, and debuted in Singapore and Malaysia on 13 March 2008.

Fiona starred in a MediaCorp Channel 8 Mandarin drama titled "Just in Singapore" which has been airing since March 2008. She plays a kind-hearted tomboy who sells chicken wings at bazaars and sings ge-tai during the Lunar Seventh Month.

Fiona starred in a MediaCorp Channel 5 sitcom titled "Calefare", which starred Gurmit Singh, Benjamin Heng, Mastura Ahmad and Vadi PVSS. She played a calafare named Joleen Wee, a singer wannabe who actually cannot sing, and often expressed herself in terms of quotes like "eyes wide open", "laugh out loud" and so on.

Fiona Xie was originally slated to be in the Channel 8 2009 year-end blockbuster, Together. She would have been playing the second female lead, the biggest role that she has ever gotten. It was announced on 15th July 2009 that she has pulled out of Together because she has private matters to attend to. She made the news once again for the sudden disappearing act, which none of the local celebrities would dare to do. Although the exact reason behind this has yet to be determined, some of the co-stars provided hints that Xie had expressed discomfort in sdoing this role. Xie is also the lead actress in her up-coming movie, 'Fist of Dragon" making it her 3rd movie. Local artiste Eelyn Kok would eventually replace her role in Together.She is placed along the likes of other young actresses such as Jesseca Liu, Jeanette Aw, Joanne Peh, Rui En, Felicia Chin and Dawn Yeoh, widely known as The Mediacorp 7 princesses.