The 1,035 metre long zip wire would run from a point just below the summit at Honister Crag to the Honister Slate Mine car park.
The wire is expected to carry 57 people a day during the summer.
Described by its promoters as a "dual purpose aerial wire for extraction of stone and tourism use", the line may also be used to transport up to 200 tonnes of slate over the course of a year.
Similar zip wire proposals submitted in 2011 and 2012 were rejected on the basis they would "harm the qualities of remoteness, tranquility, and wilderness" of the landscape.
According to a planning report, the latest proposal generated more than 100 written objections and opposition from groups including government agency Natural England and the campaign group Friends of the Lake District.
However, Borrowdale Parish Council supported the proposal and said: "Without development such as this, the valley will stagnate."
Officers recognised the latest plan would bring "a unique attraction to the area" and said the newly proposed dual function of the zip wire was a factor in favour of approval.
The zip wire would "broaden the existing tourism experience at Honister" and "facilitate the extraction of historically quarried slate", they said.
The principle of further development at the site was consistent with development plan policies for the open countryside, officers added.
However, they concluded: "Despite the weight we have attributed to the identified benefits, they do not in our view outweigh the adverse landscape and visual effects identified and the harm to the special qualities and outstanding universal value of the Lake District."
Nevertheless, planning committee members approved the plans by seven votes to three, subject to conditions being agreed.
Similar tourist attractions are increasinlgy common around the country. In 2016, a kilometre-long toboggan run was approved in the Snowdonia National Park. Also in 2016, plans were approved for a 300-metre-long zip wire along Brighton seafront.