Mutawakil is being held at the Kandahar base
US military officials in southern Afghanistan are now questioning Wakil Ahmad Mutawakil at their base at Kandahar. The city was formerly the centre of Taleban power.
Mr Mutawakil was a close associate of the fugitive Taleban leader Mullah Mohammed Omar and is the highest-raking Taleban official so far to be taken into custody.
The US military hopes that Mr Mutawakil will provide important intelligence about the Taleban and Osama Bin Laden's al-Qaeda network.
Mr Mutawakil surrendered to the Afghan autorities in Kandahar, who handed him over to American military custody.
"As we've done with people that have turned themselves in, we will question him," Major Brad Lowell, a spokesman for the US Central Command, told Reuters.
"If we take any detainees we would hope to get some information," he said.
Taleban spin doctor
The BBC's Kate Clark in Kabul says it is not known what kind of a deal was reached for Mr Mutawakil's surrender but he may have valuable information, perhaps even on the whereabouts of Mullah Omar.
However, as a relative moderate, more hardline Taleban officials may not have shared key information with him, she says.
Mr Mutawakil played an important propaganda role for the Taleban, putting a gloss on systematic human rights abuses, our correspondent says.
He also privately voiced concern about the increasing influence of Bin Laden and other Arab militants.
Forces regrouping
Despite the US campaign, very few senior Taleban figures have been caught and most members are still at large.
Although the Taleban's power base has been smashed, there are signs that some are regrouping.
One political party of relative moderates has been established in neighbouring Pakistan, and there are reports of a more shadowy hardline faction re-forming inside Afghanistan.
New legislation to allow the formation of political parties is due to be passed soon.
Interim Foreign Minister Abdullah Abdullah has said former Taleban would never be allowed to establish parties, but the interim justice minister, Abdulrahim Karimi, has told the BBC it would be up to the Supreme Court to decide.