In a national address from the balcony of the White House Blue Room, Mr. Biden indicated that “justice has been delivered.” His remarks come after authorizing the strike that killed the man, one of the masterminds of the 9/11 terror attacks.
“This terrorist leader is no more,” Mr. Biden added, before expressing his hope the killing brings “one more measure of closure” to families of the nearly 3,000 people who died in the attacks on 11 September 2001.
The president added that Afghanistan will “never again become a terrorist safe haven” after the strike was carried out nearly a year after US troops withdrew from the country.
On Sunday morning the Egyptian terror leader was standing on the balcony of a safehouse in downtown Kabul when he was killed by two hellfire missiles fired from a drone.
Mr. Biden however reported that none of the 71-year-old’s family members were injured and no civilian casualties were recorded.
The US president said: “The United States continues to demonstrate our resolve and our capacity to defend the American people against those who seek to do us harm.
“We make it clear again tonight that no matter how long it takes, no matter where you hide if you are a threat to our people, the United States will find you and take you out.”
As parts of efforts to apprehend Ayman al-Zawahiri ,the FBI had been offering $25m (£20m) for “information leading to the apprehension or conviction” of the terror leader, whose death comes as a big blow to al Qaeda since the death of their founder Osama bin Laden who was killed by special forces of the US in 2011.
According to a senior US administration official, the plan to kill al-Zawahiri was months in the making.
On July 1 of this year, Mr. Biden received his initial briefing regarding a planned operation to take out  the al Qaeda leader.
But it was much earlier in the year when intelligence suggested that his wife and children had relocated to Kabul. He and his family were believed until that point to have been in hiding in Pakistan.
The family was discovered in a safehouse where, according to the US official, al-Zawahiri was eventually discovered as well.
His pattern of life was recorded after several months of being watched. He never left the house but did spend time on a balcony where he was eventually killed.
On 25 July, a detailed proposal had been presented to Mr. Biden who, the administration official said, requested “granular level interest” because of the focus on taking “every step… to minimize civilian casualties”.
Intelligence allowed the Americans to study the construction of the house to ensure that civilian casualties were avoided.
The official added that al-Zawahiri’s death is “a significant blow to al Qaeda and will degrade their ability to operate”.
Richard Moore, head of the UK’s intelligence service MI6, said his thoughts were with the families of those killed by al-Zawahiri’s atrocities.
Mr. Moore tweeted: “Tough job professionally done by our US allies. The culmination of a long, shared effort since 9/11 to eliminate the threat posed by Zawahiri – a man responsible, with his toxic creed, for the death of so many these past three decades.”