John Jenkins, 95, of Milton, completed the challenge to raise money for Rowans Hospice.
Mr Jenkins said he enjoyed the descent, which was his first ever abseil.
He said: ‘It was quite exciting. There was a tremendous view and you could even see Fratton Park,’ he said.
Mr Jenkins is a boardroom steward at Fratton Park, where he has worked for the past 62 years.
Amanada Mahoney from the Rowans Hospice said she wanted to thank Mr Jenkins for his ‘extraordinary achievement.’