[1] Wong began her acting career by participating in the Miss Hong Kong 2007 beauty pageant, where she was placed among the top 5 finalists.

[3] Born in Hong Kong, Mandy Wong was raised in a single-parent household and graduated from Cognitio College (Kowloon).

She has an older sister, Cathy Wong, who was a former English language specialist at King's Glory Education Centre.

Wong was offered an artiste contract by TVB, upon graduating from its acting class in 2008, and debuted with an uncredited appearance in the sitcom Best Selling Secrets.

Impressed with her character portrayal, producer Poon Ka-tak cast Wong to portray "Cheng Siu-man", the timid younger sister of Flora Chan's character in the 2010 romantic comedy drama Suspects in Love, again receiving attention from netizens.

In 2012, Wong's popularity further rose and was highly praised by netizens with her role as "Lau Siu-lan", the overbearing wife of Oscar Leung's character in the family drama L'Escargot, for which she won My Favourite Most Promising Female Artiste award at the 2012 MY AOD Favourites Awards.

In 2013, Wong starred in the romance drama Always and Ever as the younger sister of Esther Kwan's character, which was her first villainous role and the producer had publicly praised her performance.

In 2014, Wong reprised her role as "So Man-keung" in the sequel Flying Tiger II, for which she garnered her first nomination for Most Popular Female Character at the 2014 TVB Anniversary Awards.

In 2015, Wong played her first female leading role in the crime drama The Fixer, for which she gained her first Best Actress nomination at the 2015 TVB Anniversary Awards.

In the same year, Wong starred in the critically acclaimed supernatural drama The Exorcist's Meter, playing "Chong Tsz-yeuk", a kind-hearted A&E doctor, and a devil named "Salvia".

In addition, she was nominated for the Best Actress in the 2017 People's Choice TV Awards by audience and netizens, eventually ranking 2nd in the category.

To prepare for her role, Wong had done research, watched numerous film and television work, and read books related to dissociative identity disorder.

[12] Wong became the first TVB artiste featured on NASDAQ MarketSite at New York Times Square and was invited as a special guest at the 17th Miss Chinese Beauty Pageant 2018 Final, which was held in August.

In her acceptance speech, Wong said, “I still firmly believe, that one’s effort may not necessarily be rewarded, but as long as we are willing to work hard, someone will see it.” She became a strong contender for the Best Actress award at the 2018 TVB Anniversary Awards, eventually placed among top 5 in both the Best Actress and Most Popular Female Character nominations.

In 2019, Wong starred in the comedy drama My Life As Loan Shark as a passionate social worker, collaborating with veterans Kent Cheng, Kingdom Yuen, Maggie Shiu.

In 2019, Wong hosted her first reality TV show, Dancing For a Reason, which was filmed in Seoul, South Korea.

[33] The international theatre news website BroadwayWorld wrote a review on this stage play, which praised Wong for her convincing imitation of an android and her transition into the endearing Chloé with memories and emotions.