Omar Hassan al-Bashir came to power in a military coup in 1989 and has ruled with an iron fist ever since.
Mr Bashir faces two international arrest warrants - issued by the International Criminal Court in The Hague - on charges of genocide, war crimes and crimes against humanity. The charges relate to the conflict in the western Darfur, where thousands of people died of violence, disease and displacement during the fighting between government and rebel forces.
He has dismissed the allegations and has continued to travel to countries which oppose the indictment.
Kenya - an ICC signatory - chose not to enforce the arrest warrant when Mr Bashir paid a visit to Nairobi in 2010, but in November 2011 a Kenyan high court judge ruled that he should be arrested if ever he set foot in the country again.
When Mr Bashir took power in the 1989 military coup against the elected government of Prime Minister Sadiq al-Mahdi he dissolved parliament, banned political parties and set up and chaired the Revolutionary Command Council for National Salvation, which ruled through a civilian government.
He formed an alliance with Hassan al-Turabi, the leader of the National lslamic Front, who became the regime's ideologue and is thought to be behind the introduction of Islamic Sharia law in the north in 1991. In 1993 Mr Bashir dissolved the Revolutionary Command for National Salvation, concentrating power in his own hands.
Mr Bashir was elected president in 1996. A new constitution was drawn up and some opposition activity was permitted.
But in late 1999 Mr Bashir dissolved parliament and declared a state of emergency after Mr Turabi tried to give parliament the power to remove the president and to reinstate the post of prime minister.
President Bashir won re-election in 2000. Supporters of his National Congress Party (NCP) filled parliament. The opposition boycotted the poll, accusing Mr Bashir of vote-rigging.
In April 2010 he won Sudan's first multi-party elections in 24 years. International observers criticised the election as falling short of international standards. Many opposition parties withdrew from the race, alleging widespread vote rigging and intimidation.
Simmering popular discontent over austerity measures - imposed in response to the fall in oil revenues after South Sudan became independent in 2011 - prompted a challenge to Mr Bashir's hold on power in 2013, when more than 30 dissident NCP members broke away and formed a new party, in what was seen as the most serious split in the leadership since Mr Bashir fell out with Hassan al-Turabi in 1999.
In December 2013, Mr Bashir responded to the calls for reform and the creation of the breakaway party by carrying out a major reshuffle of his cabinet, dropping long-serving loyalists such as Ali Osman Taha - a key figure ever since the 1989 coup - and bringing in some new faces.