Sam Pilcher, 31, was climbing with a friend in the Lake District on May 27 when he fell approximately 60ft from a sheer crag at around 1.30pm.
He banged his head underneath the helmet he was wearing and suffered a “very serious" injury. He "would have survived" if he had landed just 20mm lower, his boss said.
Rescue personnel rushed to the scene, Quayfoot Buttress in Borrowdale, and treated Sam there before flying him by air ambulance to Newcastle Hospital.
Sadly, he died in hospital on May 30.
Sam worked as an instructor for a climbing centre called Kong Adventure in Keswick, Cumbria, which has confirmed the incident and details surrounding it.
Manager Lou Osborn said: "It was a total freak accident. He was so unlucky. If he had fallen 20mm lower he would have survived. He did everything right but was really unfortunate."
She added: "Sam was great. He was so passionate about his job and always wanted to help others. He was a very positive, happy person and bonded really well with everyone. Sam was especially good at working with children, especially those with certain difficulties."
Lou said all of Sam's colleagues were in "shock" at hearing the news of his death.
She added: "We were all stunned. We couldn't believe it. Everyone was really distressed. It couldn't have happened to a nicer person."
Kong Adventure confirmed the sad news of Sam's death on Facebook this week.
They posted: "It is with great sorrow that we share the news that one of our instructors lost his life last week. Sam Pilcher was out climbing with a friend when he suffered a tragic freak accident at Quayfoot Buttress in Borrowdale.
"Sam joined our team in February 2020 and instantly brought enthusiasm, drive and passion to his job. He was exceptionally hard working and was extremely popular with all of our staff and customers and quickly bonded with all of those he taught."
Keswick Mountain Rescue Team confirmed they were called to Quayfoot Buttress on May 27 after a member of the public saw Sam fall and dialled 999.
Two vehicles initially attended and personnel went to the crag top to perform a roped rescue, lowering a team paramedic down to the casualty.
Sam was lowered to the bottom and treated by rescue members and air ambulance paramedics who carried out an assessment and performed some initial treatment.
He was then stretchered down to a car park to an awaiting ambulance before being transferred to the air ambulance for onward transfer to hospital.
A Keswick Mountain Rescue Team spokesman said: "Many thanks to the coast guard helicopter which was also called due to the nature and seriousness of the incident in case of the need for a winch evacuation."
Kong Adventure confirmed Sam, who lived in Ambleside, had recently joined a Lake District mountain rescue team and was "excited" to help out with upcoming rescues.
His employer added: "Sam was passionate about helping out others who were vulnerable or were having difficulties in their life."
According to Kong Adventure, Sam recently climbed 18 of the oldest routes in the Lake District in the type of footwear that was available in the olden days.
He wanted to raise awareness and support the group Dewolf bushcraft which offers sanctuary and support for emergency service workers, NHS staff and veterans.
Since news of Sam's death emerged, dozens of tributes have poured in on social media.
Luke Collyer posted: This man Sam was an awe-inspiring lad. Genuinely caring and a great inspiration."
Lucy Ann Fuggle said: "A fantastic inspiration to all young climbers. You will be sadly missed by all kids and parents who come to climbing clubs."
Lib Berkeley added: "So sorry to hear this. Sam instructed us recently and our three children thought he was wonderful."