(CNN) -- A teenager with cancer who touched the hearts of many in the United Kingdom with his tireless fundraising efforts died Wednesday at age 19, his mother said via Facebook.
It is news that will sadden many supporters won over by Stephen Sutton's mix of determination, generosity and good humor in the face of his terminal illness.
While he lost the battle to stay alive, he achieved a remarkable feat: Having set himself the challenge of raising some $17,000 for a teenage cancer charity, he ultimately inspired over $5.4 million in donations.
On his website, Stephen's Story, he tells how he was first diagnosed with cancer in 2010, at age 15.
"In a weird way, I see my first cancer diagnosis as a good thing. It was a huge kick up the backside. It gave me a lot of motivation for life."
He created a "bucket list" on Facebook of 46 things he wanted to do before he ran out of time.
"Some things on my bucket list include sky diving. Crowd surfing in a rubber dinghy. Playing drums in front of a huge crowd. I ended up doing it live at Wembley. Hug an animal bigger than me."
But, he says, as he checked off each item, something else happened.
"Since starting the bucket list, I've had people come up to me and offer to raise funds for me. To go on holiday or tick off a new item on my bucket list. But I've actually refused. And decided to give the money to charity instead."
That decision led to a stupendous fundraising effort that won him the backing of celebrities and the general public, despite doctors telling him in November 2012 that his illness was terminal.
On the Facebook page he set up to run that effort, Stephen's Story, he describes himself as a "teenager with incurable cancer just trying to enjoy life as much as possible, while raising funds for charity to help others."
And when his condition took a turn for the worse this spring, the news made national headlines.
After rallying briefly, he was readmitted to a hospital Sunday with breathing difficulties.
With typical fortitude, the last post he wrote said, "Fingers crossed the issue will be resolved and that I'll be out of hospital soon, I'll keep you all updated with how I'm getting on."
On Tuesday, a message on his Facebook page from his family said that his breathing trouble was caused by the regrowth of tumors blocking his airways and that he was no longer able to communicate.
A day later, his mother posted: "My heart is bursting with pride but breaking with pain for my courageous, selfless, inspirational son who passed away peacefully in his sleep in the early hours of this morning, Wednesday 14th May.
"The ongoing support and outpouring of love for Stephen will help greatly at this difficult time, in the same way as it helped Stephen throughout his journey. We all know he will never be forgotten, his spirit will live on, in all that he achieved and shared with so many."
Since his death was announced, donations have poured in.
The money Stephen raised went to the Teenage Cancer Trust, the charity that helped him through each surgery and each round of radiation and chemotherapy he underwent during nearly four years battling the disease.
CNN's Carol Jordan contributed to this report.