She was named after the American country singer, Brenda Lee. The daughter of a pianist, Brenda began singing to her mother's accompaniment at a very young age. At the age of five, she already had tourists paying to hear her sing. Producer Koloi Lebona heard about Brenda and brought her to Soweto to live with his family. She soon joined the group Joy and later formed her own band, Brenda and the Big Dudes.

Fassie began a solo career in the 1980’s, working with producer Sello Chicco Thwala. Her career skyrocketed in the late 1980’s and early 1990’s. Things seemed to all go downhill in the mid 1990’s when rumours of drug abuse began to surface.

After a few stints in rehab, Fassie made a comeback in 1998 with the release of her very successful album, Memeza, which was also a reunion with her long time producer, Thwala.

She died on 9 May 2004 after spending two weeks in a coma. Her death was reported to have been caused by a cocaine overdose.