Abdel Fattah el-Sisi was the defence minister in the government that was formed after the army-led ousting of former President Mohamed Morsi, but resigned on March 26 and announced his decision to run for the presidency in Egypt's upcoming elections.
Sisi has presented himself and the army as "guardians of the people's will," often using colloquial, sometimes sentimental speeches to address the nation.
Thousands of Muslim Brotherhood supporters have been arrested since Sisi came to power in July, last year.
Sisi said the army's intervention was an obligation, not a choice, because the people's demands had gone unheeded by Morsi’s Muslim Brotherhood-backed government.
"I swear to God, we were told by an official that they came to rule for 500 years. But how could they?" he said.
Morsi's appointment of Sisi to replace Field Marshal Mohamed Hussein Tantawi was praised by revolutionaries, who later pitted the young army leader against his president.
When Sisi was named the new general commander of the army and chairman of the Supreme Council of the Armed Forces, some speculated a possible alliance may have formed between the military and the new Islamist leaders, to which the army had previously been hostile.
Known to be religious, Sisi was accused of being too close to the Muslim Brotherhood.
But like many Egyptian army officers, Sisi was also a fervent admirer of Egypt's nationalist President Gamal Abdel Nasser. Supporters compare Sisi's challenge to mounting international pressure on Egypt to the actions of the much-idolised Nasser.
Born in Cairo in November 1954, Sisi graduated from an Egyptian military academy in 1977 with a diploma in military sciences.
He continued to train in the UK Joint Services Command and Staff College in 1992, and received a master’s degree at the US Army War College in Pennsylvania in 2006.
Sisi, who does not have combat experience, served as a military attache in Saudi Arabia during Mubarak’s regime.
He then became chief of staff to the commander of the northern military zone. When the military council took power after the revolution, he was appointed as the head of military intelligence in February 2011.
Criticised over 'virginity tests'
Sisi has come under criticism for defending "virginity tests" applied to female protesters during the revolution, which he said were conducted to "protect girls from rape as well as the army from possible allegations". However, he later pledged to ban virginity tests.
He has said in the past he is keen on "increasing the efficiency of the armed forces", seen to be outdated and currently struggling to restore order in the troubled Sinai Peninsula area.
Politicians and journalists who have met Sisi believe his main preoccupation is rebuilding the army's reputation, tarnished by its time in control of the country with the Supreme Council of the Armed Forces.
The army chief is also known for his close relationship with the US military.
The US has not cut the $1.3bn in annual aid it supplies to the Egyptian military in the wake of last July's ousting of Morsi and the violent dispersals of the pro-Morsi sit-ins, though it cancelled joint military training exercises in September.