Smith grew up in Houghton, Johannesburg and was a prolific run scorer in school cricket at the King Edward School in Johannesburg. He played 3 'Tests' for South Africa Under-19's and 7 one dayers for them. He was unsuccessful in the Tests, only managing one fifty but managed 5 half centuries in the shorter form which gave him an average of 84 from his 7 games.
He made his Test debut for South Africa in 2002 in Cape Town against Australia, batting at number three. The second innings of the match saw him notch his first half-century.He showed his talent in the tour of England in 2003 when he made double centuries in consecutive Test matches: a national record of 277 at Edgbaston, and 259 at Lord's. His score of 259 at Lord's is, in fact, the highest score at the ground by a foreign player. The previous record was 254 by Sir Donald Bradman.