But the deal hit a roadblock when a Sardinian court overturned a 2014 ruling allowing the sale and, amid protest from locals over a foreigner claiming ownership, the Italian government passed legislation that enabled a state buy-back.
Although the Italian Government took back the island and reimbursed Mr Harte, he successfully appealed the decision and Italy's National Park Authority was ordered to hand custody over to Mr Harte, who was given 60 days to pay $5 million.
However, the businessman appears to have now given up on the project.
Sardinian newspaper La Nuova Sardegna reported that Mr Harte's lawyer had written to local mayor Luca Montella to announce his waiver of the purchase.
In a letter, Mr Harte's lawyer cited uncertainty around the island's classification as a reserve, as well as "persistent opposition" to his conservation plan, for walking away from the deal.
[NZME-NZG-NZC]
-NZH