Jill is of mixed parentage with a father with ancestry in Cebu, Philippines and a Chinese Korean mother from , South Korea.
She is also known by the Chinese name, Wei Shi and educated up to secondary school. She can speak Cantonese, English and Korean. Apart from music and singing, she is also into dancing, art and fashion. Currently, she is managed by Paciwood Music & Entertainment and by in Korea.
By the end of 2005, Jill entered into a contract with the East Asia Record Production, who also have a contract with . She released her first song, ''Lonely'' in December 2005. Her voice is virtually identical to 's, but she has a notably different style to her sister's. Jill's songs tend to be more influenced by hard-core R&B and are also more fast-paced.
Jill released her debut album '''', in 2006. In July 2006, her song ''Funny Jealousy'' became her first number 1 song in the Jade Solid Gold chart.
She made her film debut in the musical film, ''A Melody Looking'' and acted as Jill, a twin sister of Janice in the film directed by Leon Lai. It was released on DVD on December 18, 2006.