Richard Thoday, 55, was aiming to beat the long-standing record of five days, one hour and 45 minutes set by Lt Colonel George Pilkington Mills in 1886. He beat it by nearly an entire day - reaching the tip of Scotland in just four days and 12 hours.
Richard, from Ambergate, Derbyshire, pedalled for around 16 hours a day since starting his journey on July 20. The learning support teacher arrived at John O'Groats at around 6pm on Wednesday complaining of a very painful "rear end".
He said: "I wanted to do this because of curiosity. I have been riding the penny farthing for 10 years. I knew about this record for a long time so I just thought I should try and beat it. The most challenging part of the ride is sitting on the seat as long as you have to. My rear end was painful but you just have to get on with it.
"I didn't fall at all. You have to stay focused on the penny farthing at all times because a pothole can make you crush. There was a day where I was cycling through a heavy storm but I managed. I was proud of the fact that I went up the hills very smoothly because the penny farthing doesn't have gears.
"I thought I was going to have to walk up the hills at first, so I wasn't expecting that. I saw some fantastic scenery especially through the Cairngorms, it was just glorious."
Richard consumed around 11,000 calories a day to keep his energy levels up on the 800-mile ride. He added: "The amount of food I had to eat was enormous. It can make you physically sick.
"I was almost sick but I just managed to carry on. It's just extremely difficult to stop every hour to eat, it's almost like a chore. The crew would tell me what to eat.
"But everyone was great and the support has been amazing, that's what kept me going."
Richard's wife Dawn, 57, and daughter Emily, 24, were supporting Richard on the mammoth journey - meeting him at checkpoints along the way.
Richard said: "No one was allowed to ride with me. But I was happy with that because you can go at your own pace. On average I think I was riding at 12mph.
"I had a few crew members who would help with food, locations to stop and would gather evidence for Guinness. I also had a film crew. It was an emotional rollercoaster and when I first started I had a little cry myself.
"You just realise how much work you've put into it and the time you've taken out of family life. But I'm so happy to have completed it. It was a once in a lifetime thing for me and I don't think I'll be doing it again."
The penny-farthing used for the more than 800-mile trek was designed by Unicycle and was based on the one Richard designed himself ten years ago. Richard took on the challenge for Children in Need and has so far raised £8,600.