Brenda Song was born in Carmichael, California, to parents of Hmong origin, on September 24, 1987. She began her professional performing career almost from infancy, and was appearing on television in commercials, series guest roles, and minor movie parts from the age of 6.

Some of her earliest appearances include a commercial for Reese's Puffs cereal, the recurring role of Kathy on ABC's Thunder Alley (1994-95), the movies Requiem (1995) and Santa with Muscles (1996), and the revival of the 1950s sitcom Leave it to Beaver (1997).

In 1999, Song landed the co-starring role of Sariffa Chung in the Nickelodeon series 100 Deeds for Eddie McDowd, a show in which she interacted with talking dogs. During the same year, the then 12-year-old appeared on ABC's Once and Again in an episode which aired in October, and The WB's Popular in