Koon also plays the Guzheng,[3][non-primary source needed] a traditional Chinese musical instrument with 21 strings, as well as the Guitar and Piano.

[5] After completing her studies in England, Koon returned to Hong Kong in 2000 where she began her modeling career for various magazines, advertisements and commercials.

Koon also starred in the popular TVB's drama series "Revolving Door of Vengeance" in 2005 and "Survivor's Law II " in 2007.

She also landed roles in movies such as My Sweetie (甜絲絲, 2004), Drink, Drank, Drunk (千杯不醉, 2005), Ice Age 2: The Meltdown (冰河世紀二, 2006), The Shopaholics (最愛女人購物狂, 2006), Without Words (地老天荒, 2006), Undercover Hidden Dragon (至尊無賴, 2006), Arthur and the Minimoys (迷你魔界大冒險, 2007), Muddy but Pure White (泥巴色的純白, 2008), Playboy Cops (花花型警, 2008), Look for a Star (游龍戲鳳, 2008), Short of Love (矮仔多情, 2009) and Ice Age 3: Dawn of the Dinosaurs (冰河世紀三, 2009).

[3] In 2006, during promoting a Mid-Autumn Festival event, Ella was assaulted on stage by a man, later identified as Kalton Pan, a 22-year-old male.