South Sudan profile - Leaders
President: Salva Kiir Mayardiit
Salva Kiir Mayardit became president of South Sudan - then still part of Sudan - and head of the Sudan People's Liberation Movement (SPLM) in 2005, succeeding long-time rebel leader John Garang, who died in a helicopter crash.
Mr Kiir was re-elected as president in multiparty polls in the south in April 2010. On South Sudan's independence in July 2011, he became president of the new state.
In mid-2013 President Kiir sacked his entire cabinet, including Vice-President Riek Machar, following a power struggle within the SPLM, later alleging that Mr Machar vice-president had instigated a failed coup.
The accusation sparked violent clashes, which soon escalated into a full-blown civil war that had forced more than 2.2 million people from their homes by 2015.
The fact that Mr Kiir is a member of the Dinka, South Sudan's largest ethnic group, and Mr Machar belongs to the Nuer, the second largest community, gave the conflict an ethnic dimension.
Government and rebels agreed to attend peace talks in Ethiopia in 2014, and a deal was finally signed under threat of UN sanctions for both sides in August 2015, despite Mr Kiir expressing "reservations".
Under the deal, it was agreed that Mr Machar would return to the vice-presidency.
Prior to independence, Mr Kiir was also vice-president of Sudan, under the power-sharing arrangements put in place in the 2005 Comprehensive Peace Agreement (CPA).
Having fought in the south's first civil war in the 1960s, Mr Kiir joined the Sudanese army after the 1972 peace agreement. He defected to the rebels again on the resumption of fighting in 1983, later emerging as the SPLM's military leader.
During a historic first visit to Sudan since independence, Salva Kiir in October 2011 ruled out a return armed conflict between the new neighbours, despite continuing tensions.
He has also taken a tough line on corruption, and in September 2011 announced several measures to combat it, including plans to subject government contracts to procurement legislation and make officials publish their assets and earnings.
Mr Kiir was born in 1951 in Bahr al-Ghazal state, and is a Christian.