The new ministers were sworn in at the Sefako Makgatho presidential guesthouse in Pretoria on Wednesday.
Constitutional Court Judge Johan Froneman presided over the ceremony.
Incoming Co-operative Governance and Traditional Affairs Minister Lechesa Tsenoli, Human Settlements Minister Connie September and Communications Minister Yunus Carrim were first to take the oath.
They were followed by Justice and Constitutional Development Deputy Minister John Jeffery, Science and Technology Deputy Minister Michael Masutha and Rural Development and Land Reform Deputy Minister Pam Tshwete.
Meanwhile, the presidency on Wednesday stated that Jacob Zuma "does not need to provide reasons" for his Cabinet reshuffle choices.
Zuma on Tuesday afternoon announced a Cabinet reshuffle, which was widely criticised by opposition parties and members of the public.
Reasons for his choices
Then, in a short statement on Wednesday headed "reasons for changes in national executive", the presidency said Zuma was not obliged to provide reasons for his choices.
"The presidency has noted complaints from some media houses and commentators that President Jacob Zuma did not provide reasons when announcing changes to the national executive. The presidency wishes to remind the opinion makers that the president of the republic uses his prerogative when appointing members to the national executive. He does not need to provide reasons," the statement read.
Zuma was slammed by opposition parties and trade unions on Tuesday for not giving Basic Education Minister Angie Motshekga the chop.
" … We considered that our call for Minister Angie Motshekga's resignation would be taken into consideration due to her underperformance," said South African Democratic Teachers' Union general secretary Mugwena Maluleke in a statement.
The biggest losers of the reshuffle were the former ministers of human settlements, Tokyo Sexwale, co-operative governance and traditional affairs, Richard Baloyi, and communications, Dina Pule. They were replaced by September, Tsenoli and Carrim respectively.
Fire underperforming ministers
The Democratic Alliance (DA) said the president should have fired all underperforming ministers.
"The reality is that this Cabinet reshuffle by President Zuma proves that he is more interested in his political survival than ensuring that good governance is his top priority," DA parliamentary leader Lindiwe Mazibuko said in a statement.
Meanwhile, Cosatu general secretary Zwelinzima Vavi echoed Zuma's sentiments.
"The president has a prerogative to make any decision in relation to the Cabinet," Vavi told SAfm on Wednesday morning.
"After all, this is about his own performance and he [Zuma] needs to go to the public next year and account as a president in terms of what he has or has not done to pursue the goal of building a better life for all." – Sapa; additional reporting by Staff Reporter