Knowles first appeared as a contestant on Young Talent Time in 1974 whilst attending Donvale Primary School east of Melbourne.
Knowles returned to Australia in 1988 and featured in the stage musical Big River during its eighteen-month national tour.
For her performance as southern belle, Mary Jane Wilks, Knowles received a nomination for a Green Room Award for Best Supporting Actress in a Musical.
In 1991, Knowles, along with the group's main songwriter Bruce Woodley and the National Boys Choir, recorded the song I Am Australian.
In 1991 Knowles recorded and produced her fourth album A Night of Carols, featuring the Australian Girls Choir.