Stephen Sutton was diagnosed with what was initially bowel cancer, when he was 15.
Despite surgery, the aggressive cancer spread to different parts of his body and and after further treatment and operations, doctors concluded it was incurable.
Fighting the disease, Mr Sutton decided to launch an inspirational fundraising campaign to give other people the motivation to "enjoy life".
Mr Sutton, from Burntwood, Staffordshire, created a bucket-list of 46 things he wanted to do before he died, setting up a charity fundraising website and a blog on social media site Facebook in January last year to keep people up to date with his progress.
He also set an initial fund-raising target of £10,000 for the Teenage Cancer Trust, but that target was smashed by a huge number of public donations as publicity around his cause spread.
He then aimed to reach a new target of £1 million, which he has now done, with more than 35,000 donations so far.
But yesterday Mr Sutton posted his final blog entry after his condition worsened.
He wrote that tumours in his chest had caused his right lung to collapse, leaving him short of breath in bed after even the smallest amount of exertion, adding "unfortunately I haven't got much time left".
Mr Sutton said: "I've done well to blag things as well as I have up till now, but unfortunately I think this is just one hurdle too far.
"It's a shame the end has come so suddenly - there's so many people I haven't got round to properly thank or say goodbye too. Apologies for that."
He added that future updates on the page would "probably be from a family member" but if he had the energy he would try and post a few tweets.
Thanking family, friends and fund-raisers he said: "That's it from me. But life has been good. Very good."
In recent months, the young man's campaign has gone from strength-to-strength with celebrities like interviewer and former newspaper editor Piers Morgan and the stand-up comedian Jason Manford offering their support on social media.
Speaking previously, Mr Sutton said he disliked the term "dying from my cancer - I am living with my cancer, despite it being there".
His bucket-list included things like hugging an elephant, crowd-surfing in a rubber dinghy, playing the drums at a Wembley cup final, getting a tattoo and appearing on BBC drama Doctors.
Explaining why he set up his bucket-list, he said it was not so much for him but to show other people that life was for living.
Mr Sutton said: "I'm stuck in this position with loads and loads of motivation but potentially not very much time but I see lots of people out there that have time."
"What I can try and do is give them a bit of my motivation, to go out there and achieve something - enjoy life," he added.