Kwong attended Epping North Public School and Cheltenham Girls High School. As a third-generation Chinese Australian, she learned the fundamentals of Cantonese cooking by her mother's side. She undertook much of her apprenticeship at Neil Perry's Rockpool and Wockpool, and later at Restaurant Manfredi.
Kwong opened her first restaurant, Billy Kwong, in the Sydney suburb of Surry Hills. 'Billy' in the restaurant's name derives, not from the name of a family member, but from the partnership with Sydney celebrity chef Bill Granger under which the restaurant was founded. Kwong later become the sole owner of the restaurant under the original name. The current Billy Kwong Potts Point is co-owned with Sydney and Hong Kong chef and restaurateur Andrew Cibej and seismologist and businessman David King.
The restaurant made a commitment to use organic and biodynamic food: "We now use only organic and biodynamic fruit and vegetables, poultry, meat and noodles. All the soy sauces, sugar, vinegar and oils we flavour our food with are organic, and we serve Fair Trade tea, coffee and chocolate." The restaurant made this transition in 2005.
Kwong is quoted as saying "I wanted my work and social life to reflect my Buddhism. Offering my customers healthy, life-giving, precious food is the best way for me to help them. Whether it's my books, restaurant or TV show, I'll always ask, Is this sustainable? Is this about uplifting and elevating the energy rather than depleting?".
Billy Kwong received the inaugural Sustainability Award in 2009 from the Sydney Morning Herald Good Food Guide, in recognition of Kwong's environmental initiatives, including the option for diners to donate to a renewable energy credits program, purchased from a wind farm in the Chinese province of Hebei. The restaurant serves only filtered Sydney tap water, offering no bottled water.
At a public lecture by the Dalai Lama on 3 December 2009 at the Sydney Entertainment Centre, Kwong acted as master of ceremonies.
On 1 October 2011, Kwong's first ever tableware range went on sale in Oxfam shops around Australia. The range, which includes a soup bowl and rice bowl with matching plates, soup spoon, teapot, teacup and coffee cup, is a joint project with Oxfam Australia and is hand-crafted by one of Oxfam's fair trade producer partners in Vietnam, Mai Vietnamese Handicrafts.
In 2003, Kylie Kwong: Cooking with Heart and Soul was published by Penguin Viking/ABC Books in October 2003 to coincide with her first TV series which was screened on the ABC at the same time. Her first cookbook Kylie Kwong: Recipes and Stories was published by Penguin in April 2003. The television series was screened both on the Australian ABC, but also on Foxtel, on the LifeStyle Channel, and on Discovery Home in the United States.
In late 2001, the LifeStyle Channel released a statement revealing that a second Kylie Kwong series would be released. The 6 part television series would be named Kylie Kwong: Simply Magic. This series was then televised in January 2006 on the LifeStyle Channel and later in 2006 on Discovery Home. A new Kylie Kwong book was released in 2006 under the name of Simple Chinese Cooking. The book aims to make Chinese cooking as easy as possible, with every recipe accompanied by a full-page colour photograph.
A third series to accompany her new book My China: Stories and Recipes from My Homeland will be shown on UKTV Food in Summer 2008.
In 2012 she appeared as a guest chef in the fourth series of MasterChef Australia.
In 2014 she appeared as a guest judge and for the first elimination round in the sixth series of
Kwong's long-time partner is Australian single-name-only artist Nell.
To date, Kwong has released five books, all of which share her love of cooking and explore many different facets of Chinese culture and cuisine. In order of release, these include:Kylie Kwong: Recipes And Stories - 2003 - 184 pages. ISBN 978-0-670-91118-9
Heart and Soul - 2003 - 204 pages. ISBN 978-0-670-04154-1
Simple Chinese Cooking - 2007 - 313 pages. ISBN 978-0-670-03848-0
My China: A Feast for All the Senses - 2007 - 482 pages. ISBN 978-0-670-01879-6
My China: Stories and Recipes from My Homeland - 2008 - 496 pages. ISBN 978-0-00-727104-7
Story in Growing up Asian in Australia - 2008