Mir Quasem Ali, 63, a key financier of the Jamaat-e-Islami party, was executed at Kashimpur Central Jail on the outskirts of the capital.
Mir Quasem Ali, 63, a key financier of the Jamaat-e-Islami party, was executed at Kashimpur Central Jail on the outskirts of the capital, for murder, confinement, torture and incitement to religious hatred during the war.
Ali was hanged at 10:35 p.m. (1635 GMT), Law Minister Anisul Haq told Reuters, days after Bangladesh's highest court rejected his final appeal against the death sentence.
The execution took place amid a spate of militant attacks in the Muslim-majority nation, the most serious on July 1, when gunmen stormed a cafe in Dhaka's diplomatic quarter and killed 20 hostages, most of them foreigners.
The war crimes tribunal set up by Prime Minister Sheikh Hasina in 2010 has sparked violence and been criticised by opposition politicians, who say it is targeting her political foes. The government denies the accusations.
The government has also rejected allegations by human rights groups that the tribunal's proceedings fall short of international standards, and the trials are supported by many Bangladeshis.
Hundreds of people flooded the streets of the capital to cheer the execution.
"We have waited for this day for a long 45 years," said war veteran Akram Hossain. "Justice has finally been done."
Media tycoon Ali is the last of a number of Jamaat leaders to be executed, having been sentenced to death in 2014 by the war crimes tribunal.
Jamaat-e-Islami, which said the charges against Ali were baseless, has called for a half-day strike for Monday in protest. It said Ali had been "hanged unjustifiably as part of the government's conspiracy to make Jamaat-e-Islami a leaderless party."
Ali's family and the party alleged law enforcers abducted his son Mir Ahmed Bin Quasem, a member of his legal defence team, last month. The security forces have said they knew nothing about the matter.
Thousands of extra police and border guards were deployed in Dhaka and other major cities. Previous convictions and executions have triggered violence that has killed about 200 people, most of them Islamist party activists, and police.
Since December 2013 four other prominent Jamaat members, including former leader Motiur Rahman Nizami, and a leader of the main opposition party, have been executed for war crimes.
Official figures show about 3 million people were killed and thousands of women were raped during the war, in which some factions, including the Jamaat-e-Islami, opposed the breakaway.