Tang is a Hakka of Dongguan ancestry. She graduated from Buddhist Sum Heung Lam Memorial College and the Hong Kong Institute of Vocational Education's Department of Fashion Design. In 2002, she joined Hong Kong music group Cookies and became the lead singer. She sang with Alex Fong in 「好心好報」, 「好好戀愛」, 「十分．愛(合唱版)」 (which won a Jade Solid Gold Award for the best duet in 2006), 「我的最愛」, 「重愛」,「七年」,「同屋主」and 「危城」. She also appeared on TVB's variety show Beautiful Cooking. Tang is able to speak Hakka, Cantonese and Mandarin. She also represented Hong Kong in volleyball since form 1 mainly as a left wing spiker or libero, but gave up to pursue a career in the entertainment industry. In March 2015, Tang, who became a fashion label founder/owner (Loey), got sponsorship from the shop to reassemble a women's volleyball team, with herself being a left wing spiker as well as the captain and founder of the team (she cannot become a captain as a libero), and participated in an open-grade C-class qualifications, where it got a record of a win and a loss. She then led Loey to play charity matches against Chinese National Volleyball team, and had trained in Taiwan against secondary school teams in late 2015.
Tang started her singing career in the music group Cookies. The main style of music from Cookies was teen pop. When Tang started her solo singing career, her record company, EMI, wanted a change to a more grown-up look and style. Some songs on her first album, Coloring Stephy, had a more mature and soft jazz influence than her previous music in Cookies. Generally, the album was widely heard and was popular, and it was certified Gold by IFPI Hong Kong.
Tang's second solo album was Fantasy. The album had a total of five editions. One was a deluxe edition which contains a DVD featuring her music videos from this album. The only difference between the other four was the color themes of the album covers: red, yellow, blue, and green, which were four different themes for photo shoots.
Her third album is Dating Stephy. This album also features different covers, and a special edition was released three months after the original release. The album also sold as well as her previous two. There was no official announcement of the certification, as Gold Label Entertainment Ltd and EMI Music Hong Kong did not participate in IFPI Hong Kong. However, the newspapers announced that Dating Stephy has sold over 30,000 in one month, and it was at least Gold certified.
In 2007, she performed at the S.U.C.C.E.S.S. Charity Gala at Vancouver, British Columbia, Canada with many other artists.
Tang performed her first headline solo concert, called "Stephy, See Thru Live 2007". It was held from December 7 to 9, 2007 at the Star Hall in Hong Kong. A live album was released featuring songs performed at this concert.
She also did a Mandarin version of "Breaking Free" from High School Musical with Anson Hu.
Tang released her new album The Red Album in November 2008. Some tracks in this album, such as "女兒紅", have led to media attention on the improvement in Tang's voice.
In July 2009, Tang published her first romance novel, Running Alongside Me (陪著我走). The book takes the form of a diary about a girl who has recently broken up with her lover. She goes on a cruise and writes about the things she sees and does. This book also includes 100+ pages of photos, making it a photo book as well.
In December 2009, Tang released her collection of "Greatest Hits" plus "New Songs" songs in a 2CD+ DVD Collection called 'Music Cafe' which includes four new songs, including Running Alongside Me, which served as the same name as her novel. The collectors edition comes with a mousepad featuring Tang's face that is available in two designs.
In 2011, Tang left her previous record company Gold Typhoon and signed to Neway Star as her new record label.
Tang and Alex Fong, her on-screen partner in films such as L for Love L for Lies, Love Is Not All Around, Marriage with a Fool and Anniversary, were in a relationship for 10 years. Their relationship was revealed by Mark Lui at his concert at the Hong Kong Coliseum in June 2013. However, on March 15, 2016, Tang and Fong announced the end of their relationship.
Cantonese Album (EP)
- Happy Birthday (2002)
- Merry Christmas (2002)
- All the Best (2003) - first album as Mini-Cookies
- 4 Play (2004)
- 4 in Love (2004)
- Holidays (2002)
- Channel Cookies (2003)
Mini Concert Album903 California Red: Eleven Fires Concert (2004)
- Coloring Stephy (2005 August 5，2nd ver：2005 September 28) (Certified Gold 25,000 units shipped in September)
- Stephy Fantasy (2006 March 28，2nd ver：2006 June 5) (has sold 20,000 copies)
- Dating Stephy (2007 February 14，2nd ver：2007 May 10) (has sold 35,000 copies in May)
- Stephilosophy (2007 December 21) (Certified Gold 20,000 units shipped in December)
- The Red Album (2008 November 27)
- Music Cafe (2009 December 23)
- No One Knows (2010 July 15)
Other Albums17 May 2006 - All About Women (金牌女兒紅) - Track 05 - Let It Flow, and Track 08 - 偏愛 (with Kary Ng (吳雨霏))
14 June 2007 - Another Chivas Music Experience Concert Live - Track 10. 愛與痛的邊緣
2002 - Delicious Cookies
2006 - 不要忘記 (Bat Yiu Mong Gei)
2007 - Stephy & Alex 十分愛
2008 - 我的最愛Stephy & Alex電影寫真
2008 - 內衣少女電影小說 (La Lingerie Movie Novel)
2009 - 陪著我走 Visual Diary (Pui Jeuk Ngo Zau)
2009 - Heart Sweet 心甜