Lindiwe Mazibuko, 31, a party spokeswoman, defeated the incumbent, Athol Trollip, a white man and veteran politician.
It is the number two position in the party.
Mazibuko enjoyed the solid backing of DA national leader Helen Zille, who is white.
Zille told South African media: “We have crossed the first Rubicon. This is a big step into the future for the DA. We are on course for [the] 2014 and 2019 [elections].”
However, the DA remains largely dominated by whites who oppose the ruling African National Congress (ANC) party of President Jacob Zuma. Analysts believe the DA may be seeking to attract more blacks in a country where blacks vastly outnumber whites.
As such ANC officials and other critics believe Mazibuko is a token. They also point out that she only has two years of experience in parliamentary affairs and has a relatively privileged background that will not appeal to the country’s poverty-stricken black masses.
Independent political analyst Nic Borain told Reuters: The [DA] party itself has treated this as a defining issue with regard to the ability to pull black middle class voters but I suspect voters will not be swayed.
In the last parliamentary elections in 2009, the DA garnered 17 percent of the vote -- up from 2 percent in 1994. The party has overwhelmingly depended on the support of white, Indian and “coloured” voters.
According to The Economist, in the last parliamentary election, DA received 96 percent of votes cast by whites, 70 percent of the mixed-race “coloured” votes, 50 percent of Indians, but only 5 percent support from blacks.
The DA dominates the Western Cape – where Zille is the premier. The party has been commended for good governance and keeping crime rates relatively low.
ANC has ruled South Africa since 1994 after the apartheid system, was dismantled. ANC has repeatedly called DA a white supremacist organization which seeks to restore apartheid.