A full-time member of the HKREP since the 1980s, Poon has devoted her career to the theatre, also having pursued training in acting and Putonghua at the Central Academy of Drama. For many years, she has played leading roles in numerous stage productions, and is among the fine actors nurtured within the HKREP.

Poon has appeared in more than a hundred productions to date. Recently, her performances in The Eccentricities of a Nightingale, Vassa Zheleznova, Blindness, A Flea in Her Ear, Copenhagen and Love You Forever have garnered acclaim from critics and audiences. She has received Best Actress nominations from the Hong Kong Drama Awards for her performances in the first five productions mentioned above, and won the 2005 Best Supporting Actress award for her outstanding performance in Peach Blossom Fan.

In April 2011, Poon took on the position as HKREP・s Literary Manager, directing her focus on dramaturgical research and arts administration.

Poon is also a dedicated playwright. She scripted, directed and played in Angel in the Box, co-wrote The Lost & Found Trilogy, participated in the Prospect Theatre・s Playwright Schemes with such pieces as A Thought, I Don・t Want to Hear and Blue Danube, and specially conceived Super Happy Star as Chinese-language drama teaching resource intended for secondary schools for the Education Bureau. In 2010, Poon created and directed Dr. Tim Ding・s Factory for the HKREP・s Black Box, which was lauded by many.

Poon is currently enrolled in the HKU Space programme on Creative Industries Management (Arts and Culture).