Born in Hong Kong, she is the fourth oldest out of six children. Her elder brother was Austin Wai. In her early years, Wai's family resided in the poor shanty town of Rennie's Mill. She didn't keep studying since she finish primary school. In her interview on Be My Guest, Wai revealed her family lost their savings due to her father's business acquaintances. Left penniless, Wai's mother, herself, and her siblings were forced to peddle goods on the streets of Hong Kong. As a teen, she often sold gum and souvenirs in Wan Chai to sailors. At the age of 14, she began taking dance lessons at the defunct Miramar nightclub and Northern style weaponry lessons from Donnie Yen's mother, Bow-sim Mark. Wai did Chinese dance for three years. Director Chang Cheh is her godfather.
Career
1977–1987: Shaw Brothers Studio
During the film shoot for Dirty Ho, the lead actress quit due to the strain of the martial arts stunts. Wai was then an extra in the film. Director Liu Chia-Liang had seen Wai's audition tape for The Brave Archer and decided to substitute her in as the lead actress. This was their first time working together. Impressed by her performance, Liu would go on to cast Wai in his other projects. Wai reached her career apex with My Young Auntie, for which she was earned the Award for Best Actress at the 1st Hong Kong Film Awards. Wai's last film with Shaw Brothers was The Eight Diagram Pole Fighter.
1988–2002
In 1987, Wai traveled to Paris, France to conduct a nude photoshoot for Playboy. The photos were taken by Byron Newman. The photo book was published in 1989. In 1999, she suffered from depression, and her career was in low ebb. She attempted to commit suicide at the age of 40.
In 2003, with the help of friends and relatives, Wai began to recover. After 2005, she quietly returned to the Hong Kong entertainment industry. In addition to film, she joined TVB and was nominated for a TVB Anniversary Award for Best Supporting Actress in 2010. In 2009, Wai won the 46th Golden Horse Awards for Best Supporting Actress for her role as a possessive mother in At the End of Daybreak. The film has also won the 16th the Hong Kong Institute of Film Critics award for Best Actress, the 4th Asian Film Awards for Best Supporting Actress, the 29th Hong Kong film awards Best Actress, the 10th Chinese movie media awards "best actress", the 10th China changchun film festival Best Actress in Vladivostok, Russia international film festival has won seven awards Best Actress.
2011–present
Wai made her first mainland TV appearance in the series The Glamorous Imperial Concubine. She took a pay cut to play Wu Zetian in her next mainland drama, Women of the Tang Dynasty. The role garnered her a Best Supporting Actress nomination at the 13th Huading Awards. In 2012, Wai officially transferred to the king of the arts and is now a contract actress. In 2013, Wai signed a one-year drama contract with HKTV. Her first role with them was as the Black Rose on Incredible Mama. She won Best Supporting Actress for the Malaysian film The Wedding Diary at the 2013 Golden Wau Awards, a ceremony celebrating Chinese language films in Malaysia. In 2014, she won the best supporting actress award at the 33rd Hong Kong Film Awards for her film Rigor Mortis. In 2017, she won the Best Actress Award at the 36th Hong Kong film awards for Happiness. In March 2018, Wai won the Excellence In Asian Cinema Award at the 12th Asian Film Awards. In October 2018, Wai was awarded the Bronze Bauhinia Star for her outstanding achievements in the performing arts industry by Chief Executive Carrie Lam. In 2018, she starred as the conservative wife of a closeted transgender woman in Tracey. The film earned Wai the Award for Best Supporting Actress at the 38th Hong Kong Film Awards and the Award for Best Supporting Actress at the 13th Asian Film Awards.