Andrew Vavasour, a direct descendent of the family who acquired the Dob Park Lodge ruin land in 1532, let out an audible sigh of relief when planning committee councillors voted six to five to approve the conversion of the scheduled monument.
Ahead of the vote, a representative for Mr Vavasour told councillors that approving the proposal was the only option left to preserve the decaying structure.
The applicant was supported by representatives of Historic England, who told councillors that the "only useful solution is for it to become habitable again".
Historic England had previously sourced a grant to install metal supports for the teetering ruin, but they confirmed that no further aid would be forthcoming.
However, Councillor Nigel Simms said he was "totally and utterly against" the proposal.
"The impact on the surrounding countryside will be immense," he added.
He was supported by Coun Pat Marsh, who called the plan a "rebuild, not a restoration".
"It is what it is, an ancient scheduled monument. Where do we go next, Stonehenge?” she said.
Coun Bernard Bateman said he was happy to support the project, given Historic England's approval of it, with the motion passing when it went to the vote.
The decision had initially been deferred when it first fronted council in December, so councillors could have a first-hand look at the proposal's impact on the surrounding countryside.
Originally built early in the 17th century, the lodge would have been used as a viewing platform for deer hunting in the 1600s.
All that remains of the lodge now are two towers standing at the building’s original three storey height.
Mr Vavasour, a London-based airline pilot, plans on making the converted building his principal residence.
Lachlan Leeming, Local Democracy Reporting Service