Supporters of Cairo's Al-Ahly celebrated the verdict in the team's club before heading toward Interior Ministry headquarters, which manages the police, for more protests.
Lawmakers had formed a fact-finding committee that found some evidence toward collusion from authorities, but the evidence was not conclusive.
Nine of those on trial are security officials, charged with assisting the attackers for failing to search for weapons as is customary and allowing known criminals to attend the game. One was a senior officer who locked the exit designated for Al-Ahly fans. Many victims suffocated or were trampled to death in the corridor trying to escape the violence. Others were thrown off bleachers, undressed, beaten with iron bars and had the words "Port Said" carved into their skin.
Police reform researcher Karim Ennarah said the lack of a proper investigation raises the specter that some of those on trial are innocent. The state prosecutor's office, tasked with investigating the case, was long run by a Mubarak holdover.
"We still operate in a state that doesn't hold its employees, specifically in the security sector, to account," Ennarah said. "There might have been democratic elections, but it still is a very undemocratic state in terms of how police work."
The most high profile case since Egypt's uprising was that of Mubarak himself. He was found guilty of failing to stop the killing of around 900 protesters. The verdict angered people who wanted him executed on charges of ordering deadly force. He was sentenced to life in prison in what even some of his opponents argue was a verdict based on flimsy evidence aimed at appeasing an angry public.
A lawyer of one of the defendants given a death sentence Saturday said this verdict too was political.
Days before the verdict, Morsi declared the victims "martyrs of the revolution", granting families up to $15,000 in compensation.
"There is nothing to say these people did anything and we don't understand what this verdict is based on," Mohammed al-Daw told The Associated Press by telephone.
"Our situation in Port Said is very grave because kids were taken from their homes for wearing green T-shirts," he said, referring to the Al-Masry team color.
The president, once a detainee under Mubarak for his political activities with the Brotherhood, had vowed to restore security in his first 100 days in office. Instead, critics say he has waged a personal campaign against anti-Brotherhood figures rather than carry out comprehensive reform.
His Muslim Brotherhood allies blamed "misleading" media outlets for enflaming the public against the government. The main opposition bloc said it holds Morsi responsible for "the excessive use of force by the security forces against protesters."
Fans of Al-Ahly, mostly young men in their teens, promised more violence in the days leading up to the verdict if the death penalty was not handed down. Their main Facebook page had called for bloodshed.
"This was necessary," said Nour al-Sabah, whose 17-year-old son Ahmed Zakaria died in last year's melee. "Now I want to see the guys when they are executed with my own eyes, just as they saw the murder of my son."
"We are not really that happy," Mohamed Ahmed, a survivor of the attack, said. "The government helped the Ultras of Port Said by blocking the gates of the stadium until people suffocated to death."
Meanwhile, Port Said resident and activist Rasha Hammouda said the city wants those involved in killings to be brought to justice.
"We have no problem with execution of those who killed, but bring everyone who is involved," she said.
Associated Press writer Mariam Rizk contributed to this report.