British-educated Sheikh Tamim bin Hamad Al Thani was named emir of Qatar after his 61-year-old father, Sheikh Hamad bin Khalifa Al Thani, announced his abdication as leader of the gas-rich Gulf state in June 2013.
Sheikh Hamad's abdication broke the mould of Gulf politics, where rulers traditionally remain on the throne until they die. Sheikh Tamim, 33, presents a younger face as ruler, at odds with the older generations in neighbouring states.
Nevertheless, under Sheikh Tamim's rule Qatar is expected to continue on the path set by his father, with his mother, Mozah bint Nasser Al Missned, remaining one of the key driving forces in the country's politics.
Taking over from his father, whose 18-year rule was marked by the emergence of Qatar as an influential player on both the Gulf and world stage, Sheikh Tamim's elevation to emir marks the confirmation of the Al Thani dynasty's grip on power in Qatar.
Al Thani family members hold many key posts in the country's government, and the smooth transition to a new emir underlines a desire for stability in an unpredictable region.
Qatar became an influential regional player under the rule of Sheikh Hamad bin Khalifa, backing the Arab Spring revolutions and siding with rebels fighting against authoritarian governments in Syria and Libya.
It is also home to the Al-Jazeera TV channel and it has won the right to host the 2022 football World Cup.
Sheikh Tamim was born in Doha in 1980, the fourth son of Sheikh Hamad. He became the Gulf state's heir apparent in 2003 after his older brother Jasim renounced his claim to the throne.
The young Tamim was sent to Britain for his education at Sherborne School in Dorset. Sherborne's only overseas branch now operates in Doha.
After achieving his A-Levels, he followed his father's example by attending the Royal Military Academy in Sandhurst.
He graduated in 1998 before being inducted into the Qatari armed forces as a Second Lieutenant. He was appointed deputy commander-in-chief of Qatar's armed forces in 2009.
It is as a sports administrator that the young sheikh has excelled. In 2006, readers of the Egyptian newspaper Al-Ahram voted him "the best sport personality in the Arab world". That year he chaired the organising committee of the 15th Asian Games in Doha, attended by all member countries for the first time.
A member of the International Olympic Committee, Sheikh Tamim also heads Doha's bid for the 2020 Olympic Games.
As well as the Fifa World Cup, Qatar will also host the 2014 Fina (International Swimming Federation) Swimming World Championships. In addition, Qatar Sport Investments, established by Sheikh Tamim in 2005, owns big-spending French football club Paris Saint-Germain.
Which sports most interest the new emir is unclear, but he has been filmed playing badminton, and seen 10-pin bowling with former Egyptian military chief Mohammed Hussein Tantawi.
Other posts held by Sheikh Tamim include chairman of the Supreme Council for the Environment and Natural Reserves, chairman of the Supreme Education Council, and chairman of the board of directors of the Qatar Investment Authority.
In 2005, Sheikh Tamim married his second cousin Sheikha Jawaher bint Hamad bin Suhaim Al Thani. They have four children.
A second marriage in 2009 to Sheikha Anoud bint Mana al-Hajri brought two further children - in total, three sons and three daughters.