The former president and military man, who ruled Egypt for 30 years before the 2011 civil revolt, walks free for the first time in six years. He was jailed for corruption and murder two months after being overthrown.
Who is Mubarak?
The former commander of Egypt's armed forces was appointed the vice president in 1975 under Anwar Sadat - a noble peace prize winner and former military man. John Waterbury said in his book The Egypt of Nasser and Sadat: The Political Economy of Two Regimes, Mubarak did not expect a promotion so significant.
Six years later, he became Egypt's president. He was sworn in eight days after Sadat was assassinated by militants during a military parade. Mubarak was sitting next to him at the time.
Mubarak ruled over Egypt for three decades with an iron fist. The last 20 years were marred by police brutality, silencing of critics, and an unwavering state of emergency imposed shortly after Sadat's death.
During his term, Mubarak contested four elections – three of which he ran in unopposed – and won with 90 percent of the votes. Elections in Egypt have garnered a history of low turnout, block voting and vote-buying.
Mubarak was eventually overthrown in 2011 when millions protested poverty, corruption and unemployment. More than 800 people died in demonstrations over 18 days. He was the first leader to go on trial in the wake of the so-called Arab Spring, a string of uprisings against corrupt and autocratic rule across the Middle East and North Africa.
He was arrested two months after he was unseated, and has since been shuttled between prison and military hospitals.
Mubarak was replaced by Mohamed Morsi in Egypt's first presidential elections in 2012.
Morsi, considered the first democratically-elected leader of Egypt, was overthrown in a military coup in 2013 and imprisoned for inciting violence and espionage. He was a member of the Muslim Brotherhood, the social and political Islamic movement born in 1928 that is now fractured due to an ongoing movement against the organisation.
Why was Mubarak in jail?
In addition to charges of corruption and misappropriation of funds, Mubarak was jailed in 2011 over the death of 239 people, when police shot down anti-government protesters.
His acquittal comes amid concerns from human rights activists' that his crimes were whitewashed.
Under Mubarak's rule, the police was used to crush dissent – hundreds of people were systematically arrested, tortured and beaten in what was deemed police brutality. Some have argued that Mubarak used Egypt's state of emergency laws that allowed anyone to be detained without charges to suppress opposition.
In January 2016, the Egyptian appeals court upheld a three-year prison sentence for Mubarak and his two sons on corruption charges. The sentence took into account time served. Both his sons, Alaa and Gamal, were freed. Before the uprising, Gamal Mubarak was primed to lead the country after his father.
Mubarak had been accused of using state funds to upgrade his family's private residences.
Why is he being acquitted?
The judge said Mubarak was innocent, something the leader maintained since the day he was sentenced in 2012.
Observers said the investigation into the murders was shoddy and that there was not enough evidence to prosecute.
"Any lawyer who worked on Mubarak's case would have gotten him an acquittal, not because he was innocent but because the case had very bad papers," Arabic Network for Human Rights Information director Gamal Eid told TRT World.
Eid also worked on the case on behalf of the victims.
Others, like the head of research organisation The Cordoba Foundation, have argued that the acquittal is politically motivated.
"In light of everything that is going on in Egypt, it can only mean that the judiciary is corrupt," Cordoba's Anas Tikriti told TRT World.
Tikriti, who is also a supporter of the Muslim Brotherhood said: "The judiciary is highly politicised".
The release fits a pattern over the past few years where Mubarak-era figures, including his sons, have been gradually cleared of charges.
This is in contrast with hundreds of Morsi supporters who were killed in a single day and thousands more jailed in August 2013, in what Human Rights Watch said was collective punishment.
What does this mean for Egypt?
"People have actually gone back to saying the days of Mubarak were better," executive director of the Egyptian Center for Rights and Freedom, Mohamed Lofty told Newsweek.
"It is a failed government, it has failed to restore Egypt to any kind of economic semblance, it is in economic free fall, relying absolutely on handouts from neighbouring or foreign states. It is run by a military apparatus," Tikriti said.
The lack of a public response to the release of a figure once vehemently opposed by the people indicates priorities have shifted in the six years that Mubarak has been out of power. The north African country is in economic downfall, the price of bread is rising, and public dissent has been quashed.
"Egypt has been going through some tough economic times, and a lot of people, especially the middle class, have almost changed their minds. Those people feel that enough is enough, let's move on," Middle East Economic Digest analyst Hossam Abougabal told TRT World. "The 2011 uprising is now being seen as the reason for the economic instability."
But for Eid, the release only signifies that change needs to happen.
"Currently, the counter-revolution is in power and what Egypt needs is a civil democratic regime."