Prime Minister Sheikh Mohammed bin Rashid al-Maktoum named eight women as he revealed his latest cabinet line-up of 29 ministers in a series of tweets.
Ohoud al-Roumi, who serves as director of the council of ministers' office, was appointed "minister of state for happiness". She will also keep her former post.
Portrait of Ohoud al-Roumi
"Happiness is not just a wish in our country. There will be plans, projects, programmes and indices. It will be part of the job of all ministries," tweeted Sheikh Mohammed, who is also the ruler of Dubai.
The new post "will align and drive government policy to create social good and satisfaction," he said earlier.
Shamma al-Mazroui, 22, was appointed state minister for youth, while Lubna al-Qassimi, a veteran minister of international cooperation and development, was handed the new post of state minister for tolerance.
"The post of Minister of State for Tolerance has been created to promote tolerance as a fundamental value in UAE society," Sheikh Mohammed wrote when he announced the reshuffle earlier this week.
The cabinet has eight new ministers, including five women, with an average age of 38, WAM state news agency said.
Sheikh Mohammed described the cabinet shake-up as the "largest structural change in the history of our federal government," merging ministries and appointing several state ministers.
The move could be seen as an attempt to cut expenditure as Gulf oil-exporters struggle to adapt to the sharp drop in their revenues after crude prices nosedived to record low levels.
An oil-rich federation of seven Gulf sheikhdoms, the United Arab Emirates is considered a safe haven spared in the wave of Arab Spring uprisings that hit the region.
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Last year its rulers sought to widen the country's nascent democratic credentials with about a quarter of its one million citizens given the right to vote.
Eighty-seven of the 330 candidates were women, who play a much larger role in public life in the UAE than in neighbouring Saudi Arabia.
But the authorities have been deeply cautious and in 2014 introduced sweeping new counterterrorism legislation that rights groups have criticised as paving the way for a crackdown on dissent of all sorts.
Citizens account for a small minority of the UAE's population of nine million which is overwhelmingly made up of foreign workers.
Portrait of Shamma al-Mazroui, 22-year-old minister for youth
The female ministers include also Noura al-Kaabi, as Minister of State for the Federal National Council, or parliament, Jamila al-Muhairi, as Minister of State for Education, and Najla al-Awar as Minister of Community Development.
Reem al-Hashimi was moved to the post of State Minister for International Cooperation Affairs, while Maitha Alshamsi kept her post as a state minister.
Several key ministries remained in the hands of members of the ruling families.
Sheikh Saif bin zayed al-Nahyan, a son of the late founder of the UAE and a member of Abu Dhabi's ruling family, has kept the portfolio of interior.
His brother Sheikh Abdullah stayed at the helm of the ministry of foreign affairs, now merged with the portfolio of international cooperation, while his other brother Sheikh Mansour remains vice prime minister and minister of presidential affairs.
Sheikh Mohammed bin Rashid himself kept hold of the defence portfolio and his brother Sheikh Hamdan stayed as minister of finance.
Oil Minister Suhail al-Mazroui remained in office.