Connor Frampton, 28, said he was left feeling ‘dizzy’ after completing 1,562 laps of his back garden in Stubbington.
But the novice distance runner said it was all worth it after raising over £2,500 for NHS Charities Together.
After completing the monotonous run in four hours and 50 minutes, Connor said: ‘My muscles ache and my hips are sore from running in circles but it was worth it to raise that amount of money for NHS staff.
‘It was very hard work - I’ve only run 12 miles before that. After 18 miles it really started to drag and I probably ended up running 27 miles in the end because the app I was using to keep track was cutting out at times.’
Explaining his reason for running the marathon, he said: ‘I’m employed but can’t do my job from home so am not really doing much.
‘The only way I’ve been able to show thanks to the NHS is by clapping but I wanted to do more and have always wanted to run a marathon.
‘I know other people are running marathons in their garden but I’m not sure many others have ran their first ever marathon in their garden.’
Connor only decided to run the marathon two days before embarking on the challenge and was inundated with support after posting his fundraising link - inspiring him to take on the challenge in the heat of Easter Friday.
Speaking of the unique challenges of running in a confined space, he said: ‘The biggest problem was getting dizzy.
‘Also knowing how many laps I had done and how many more I had to do was demoralising at times.
‘I was counting the laps but I had my partner to take over and count when I was zoning out. I couldn’t have done it without her. We also had a scoreboard to cross off every half-mile or mile.’
He added: ‘The grass is now ruined but a bit of water and it will be ok.’
To donate go to: www.justgiving.com/fundraising/Connor-frampton