In 2008, his party lost to his closest rival, Tsvangirai, who did not get enough votes to avoid a runoff. Opposition party supporters were beaten, tortured and killed, rights groups said, and Tsvangirai withdrew from the runoff in protest. The post-election violence left about 200 people dead and thousands injured.
Regional leaders dismissed that election as a sham and pressured the two to form a power-sharing agreement, which led to a tense coalition in 2009. Mugabe's main opponent became his prime minister, and the squabbles continued.
Born in February 1924 in then-Rhodesia to a carpenter father, Mugabe spent his early career as a teacher.
His first wife died in 1992, and he married his current wife, Grace, four years later. They have two sons and one daughter.
Mugabe has university degrees in education, economics, administration and law from the University of London.
In 2002, the European Union imposed sanctions on Mugabe and his allies, including travel bans, accusing Zimbabwe of human rights violations.
In 2008, the United Kingdom stripped Mugabe of an honorary knighthood awarded by Queen Elizabeth II. Later that year, the nation plunged into post-election violence.
The European Union eased the sanctions after a successful referendum on a new constitution in March of this year but called for credible elections.
As he has continued to lash out at the West, donors have distanced themselves, sending Zimbabwe on a downward economic spiral.
By 2008, the nation's inflation had soared to 200 million percent. Food shelves were empty, and a loaf of bread cost about 300 billion Zimbabwean dollars.
International isolation continued to hit the economy as corruption remained rife.
Despite widespread poverty, the nation has made major strides in its economy in recent years, experts say. There is food on the shelves, schools and hospitals are open and farming is showing signs of recovery.
Since 2010, the nation's gross domestic product "has grown by an average of over 7 percent and inflation has remained in the low single digits," the International Monetary Fund said last month. "Government revenues have more than doubled from 16 percent of GDP in 2009 to an estimated 36 percent of GDP in 2012, allowing the restoration of basic public services."
Illness has come with Mugabe's advancing age.
He has reportedly made regular trips to Singapore for medical treatment amid growing concerns about his health. In 2011, public documents showed he amassed a staggering $29 million in travel expenses. WikiLeaks released cables detailing party members' reports that he is suffering from cancer, which he has denied.
Despite the reports, a Freedom House survey last year showed that Mugabe's party was regaining its popularity.