Sheikh Sabah al-Ahmad Al Sabah gave the energy post to Sheikh Ali al-Jarrah Al Sabah, an energy sector outsider but a member of the ruling family, which also retained the foreign, defence and interior posts, state media said on Monday.
The previous cabinet resigned after parliamentary polls on June 29. The general election, which was swept by reformists, was held after the amir dissolved parliament amid a deadlock with the government over electoral reforms.
Sheikh Ahmad al-Fahd Al Sabah, the outgoing energy minister, and other cabinet members had been accused by members of parliament of trying to influence the polls and to block reforms, charges they denied.
No change expected
The oil policy of Kuwait, which has about a tenth of proven global oil reserves, is not expected to change as it is set by a supreme council that includes the prime minister, analysts said.
Kuwait now produces about 2.6 million barrels a day.
Muhammad Sharar, the outgoing state minister for cabinet and parliament affairs who had also come under attack from opposition and pro-reform figures, was also replaced.
Kuwaiti newspapers said Sheikh Ahmad, who like the prime minister is a nephew of the amir, may head the National Security Council.
The new oil minister, an economist, has previously held the labour post.
There were three new faces in the 15-member cabinet while other ministers were given new portfolios, state media said.
Powerful Islamists and reformists swept the polls, raising the possibility of deeper tension between the government and the outspoken assembly, especially over electoral reforms.
Parliament convenes on July 12 to elect a speaker.