"We have removed the leader of an organization that has continued to plot against and unleash attacks on American and Coalition forces, to wage war against the Afghan people, and align itself with extremist groups like al-Qaeda," the US president said in a statement.
Obama, who is on a three day visit to Vietnam, said Mansour had rejected efforts "to seriously engage in peace talks and end the violence that has taken the lives of countless innocent Afghan men, women and children."
He called on the Taliban's remaining leadership to engage in peace talks as the "only real path" to ending the attritional conflict.
Mansour, who was elevated to the leadership of the Taliban after a bitter power struggle, was killed Saturday in a remote part of Pakistan's western Balochistan province.
The raid was the first known US assault on a top Afghan Taliban leader on Pakistani soil and dealt a heavy blow to the militant group which, had expanded its operations under Mansour's guidance, AFP reported.