His aides were released earlier.
'Nawaz Sharif asks why he was ousted? "He wanted friendship with India and completely ignored the Kashmir cause", he said and warned the PML-N government not to bow before the worldwide community for loans.
Saeed, who carries a $10 million bounty announced by the U.S. for his role in terrorist activities, was released just after Thursday midnight, after a Lahore High Court review board turned down the government's arguments that he was a threat to public safety.
In a statement, the U.S. Embassy in Islamabad said, "The United States is deeply concerned that Lashkar-e-Tayyiba (LeT) leader Hafiz Seed has been released from house arrest in Pakistan".
A US official said Washington was "deeply concerned" about the release. He, however, has repeatedly denied involvement in the 2008 Mumbai attacks. A court on Wednesday said that Pakistani government had failed to present convincing arguments as it sought a three-month extension on Saeed's house arrest.
She said the Pakistani government should make sure that he is arrested and charged for his crimes.
US State Department spokeswoman Heather Nauert said Saeed's terror organisation, Lashkar-e-Taiba, is responsible for the deaths of hundreds of civilians, including American citizens who were killed in the Mumbai attack.
The assault brought nuclear-armed neighbours Pakistan and India to the brink of war.
"I'm happy that no allegation against me was proved, which could have done damage to me, or my country's interests", Saeed told supporters after his release in the city of Lahore, according to a video released by the Jamaat-ud-Dawa (JuD), which he heads.
Saeed has long campaigned in support of Muslim separatists in the Indian-ruled portion of the divided Himalayan region of Kashmir, which Pakistan also claims.
New Delhi also accuses the LeT of carrying out terror attacks in other parts of India, including Jammu and Kashmir, where a separatist campaign backed by Pakistan and raging since 1989 has left thousands dead.