On Sunday, Prince Mishaal, 43, replaced 73-year-old Prince Khaled, who had been holding the position for the past six years, the Saudi state media reported.
The king appointed the outgoing Meccan governor as the new education minister.
Mishaal had been the governor of the southwestern region of Najran, bordering Yemen.
The shakeup comes as the kingdom has also announced the overhaul of the Interior Ministry and some of the other administrative bodies.
King Abdullah has recently placed several young princes in key posts amid a growing power struggle within the royal family.
Among his other sons, Mutaib is the head of the Saudi Arabian National Guard, Abdulaziz is the deputy foreign minister, and Turki is the deputy governor of Riyadh.
There are reports of the House of Saud being on shaky grounds as the spy chief Bandar bin Sultan is said to have been lobbying to remove Crown Prince Salman bin Abdulaziz from power, and install his favorite Prince Muqrin instead.
The leadership in Saudi Arabia is unlike that of any other monarchy. It is a system where princes often marry multiple wives and thus produce dozens of progeny each -- now adding up to nearly 7,000 princes.
PressTV