The leaked documents show that US officers gathered intelligence suggesting that Gul ordered suicide and roadside bomb attacks on Nato troops, and met with senior Taliban officials to plan operations against international forces.
If true, the documents would confirm what the Afghan government has maintained; that senior Pakistani intelligence figures are involved in arming, training and funding the Taliban in Afghanistan.
In one classified "threat report", Gul is said to have ordered the planting of magnetic mines, to be hidden in snow on roads, where they would attach themselves to passing military vehicles and could then be remotely detonated to wreak havoc in Afghan cities.
"Gul's final comment to the three individuals was 'make the snow warm in Kabul' basically telling them to set Kabul aflame," the report said.
Another accuses him of meeting with Arab fighters in Pakistan's tribal area to plan a series of suicide bombings in Afghanistan.
Gul is also named in a report that outlines plans to kidnap UN workers to use as a bargaining chip for Pakistanis imprisoned by the US in Afghanistan for involvement in the conflict.
But the former spy chief insists he is being used as a "convenient whipping-boy" for the failings of the US-led mission in Afghanistan, and points out that there is no hard evidence against him.
"They took my case to have me declared an international terrorist to the UN sanctions committee and it was vetoed, or placed technical hold on, by the Chinese because they could not produce any evidence," he said.
The leaked documents are not the first time that Gul has been linked to the Afghan conflict. Earlier reports have said he is contact with senior insurgent leaders, including feared commanders Baitullah Mehsud and Jiluddin Haqqani.
"I consider American and Nato forces as aggressors- in pursuit of a vicious agenda for the region"
former head of Pakistan's intelligence service
Gul denies having met the men and describes himself as an "ardent friend of Afghanistan," although he is known for his vocal opposition to the US-led military presence in the country.
"I consider American and Nato forces as aggressors - in pursuit of a vicious agenda for the region, especially Pakistan and believe that the Afghan national resistance is fully justified," he said in 2008.
He insists this opposition is "strictly a moral and academic position" and says he had "never provided any material or financial support to the resistance".
But Haroun Mir, the deputy director of Afghanistan's Centre for Research and Policy Studies, said he thought Gul was indeed linked to senior Taliban figures.
"He is still very active in this insurgency in Afghanistan," he said on Monday. "He has been seen in meetings with top Taliban leaders."
Reports naming Gul are among hundreds included in the leaked documents that implicate the ISI in supporting the Taliban.
Some of the documents contain allegations of elaborate and implausible plots.
One warned that the ISI and local groups were planning to spike alcoholic drinks and "use them for poisoning" international troops in Afghanistan; another that the ISI were offering bounties on the heads of Indian workers in Afghanistan.
Some analysts have cast doubt on the veracity of many of the claims made in the intelligence reports, pointing out that few of the alleged plots ever showed any signs of getting off the ground.
"Just about everything which I have been through on this category is rubbish," Michael Semple, a former deputy head of the EU mission in Afghanistan, said.
"Not just rumour, but complete fabrication. This applies to the tales of the adventures of Hamid Gul. He is a man with a reputation and he is a propagandist, so fabricators tell multiple tales about him."