LONDON — Capt. Tom Moore, the World War II veteran who walked into the hearts of a nation in lockdown as he shuffled up and down his garden to raise money for health care workers, has died after testing positive for COVID-19. He was 100.

His family announced his death on Twitter, posting a picture of him behind his walker in a happy moment, ready for an adventure.

"The last year of our father's life was nothing short of remarkable. He was rejuvenated and experienced things he'd only ever dreamed of,'' the family's statement said. "Whilst he'd been in so many hearts for just a short time, he was an incredible father and grandfather, and he will stay alive in our hearts forever.''

Captain Tom, as he became known in newspaper headlines and TV interviews, set out to raise 1,000 pounds for Britain's National Health Service by walking 100 laps of his backyard. But his quest went viral and caught the imagination of millions stuck at home during the first wave of the pandemic. Donations poured in from across Britain and as far away as the United States and Japan, raising some 33 million pounds ($40 million).

For three weeks in April, fans were greeted with daily videos of Captain Tom, stooped with age, doggedly pushing his walker in the garden. But it was his sunny attitude during a dark moment that inspired people to look beyond illness and loss.

"Please always remember, tomorrow will be a good day," Moore said in an interview during his walk, uttering the words that became his trademark.

FILE – In this Aug. 3, 2020 file photo, Captain Sir Tom Moore walks down a guard of honour during a visit to the Army Foundation College in Harrogate, England, as part of his new role as Honorary Colonel of the Northern military training establishment. (Danny Lawson/PA via AP, File)

When Captain Tom finished his 100th lap on April 16, a military honor guard lined the path. The celebration continued on his birthday a few days later, when two World War II-era fighter planes flew overhead in tribute. Moore, a plaid blanket over his shoulders, pumped a fist as they roared past. 

In July, he was knighted by Queen Elizabeth II in a socially distanced ceremony at Windsor Castle, west of London. The 94-year-old monarch used an impossibly long sword to confer the honor as Moore, wearing his wartime medals on his chest, leaned on his walker, beamed and became Sir Tom. 

"I have been overwhelmed by the many honors I have received over the past weeks, but there is simply nothing that can compare to this," he tweeted after the ceremony. "I am overwhelmed with pride and joy."

Queen Elizabeth II plans a private message of condolence to the family, Buckingham Palace said. 

"Her Majesty very much enjoyed meeting Capt. Sir Tom and his family at Windsor last year,'' the palace said in a statement. "Her thoughts, and those of the Royal Family, are with them, recognizing the inspiration he provided for the whole nation and others across the world."

Born in Keighley, West Yorkshire, on April 30, 1920, Moore completed an apprenticeship in civil engineering before being drafted into the army during the early months of World War II. After being selected for officer training, he rose to the rank of captain while serving in India, Burma and Sumatra.

After leaving the army in 1946, Moore went to work for the family construction firm. After that failed, he became a salesman and later a manager for building materials companies. When the concrete company he was working for was threatened with closure, Moore rounded up a group of investors and bought it, preserving 60 jobs.

Along the way, he divorced his first wife and fell in love with his employer's office manager, Pamela. The couple married, had two daughters and eventually retired to Spain, but returned to England after Pamela Moore became ill.

FILE – In this Friday, July 17, 2020 file photo, Captain Sir Thomas Moore receives his knighthood from Britain s Queen Elizabeth, during a ceremony at Windsor Castle in Windsor, England. (Chris Jackson/Pool Photo via AP, File)

After his wife died in 2006, Moore moved to the village of Marston Moretaine in Bedfordshire to live with his younger daughter, Hannah, and her family.

The former motorcycle racer slowed down at age 98 after he fell and broke his hip in 2018. A walker replaced his Skoda Yeti, but he kept moving.

During a backyard barbecue in early April of last year, Moore's family challenged him to walk the entire length of the 25-meter (82-foot) driveway. After he made it to the end, his son-in-law encouraged him to keep going, offering to pay 1 pound for every lap and suggesting a goal of 100 laps by Moore's 100th birthday.

The challenge snowballed from there.

Moore thought he might be able to raise 1,000 pounds ($1,363) for the doctors and nurses who took care of him after he broke his hip, and his family used social media to publicize "Captain Tom Moore's 100th birthday walk for the NHS." A local radio reporter called first, then national broadcasters. Soon, international media were waiting outside the garden gate.

As he pushed his walker up and down the garden's path, people facing the U.K.'s first lockdown of the pandemic watched online. Soon, #TomorrowWillBeAGoodDay was trending on Twitter.

"People told me that there was something about my little walk that captured the hearts of those still in shock at the crisis," Moore wrote in his autobiography. "With a rising number of deaths and the prospect of months of lockdown, everyone was desperate for good news. Apparently, a 99-year-old former Army captain who'd fought in Burma, was recovering from a broken hip, and doing his bit for the NHS was just what they needed."

Prince Harry, Prime Minister Boris Johnson and dozens of celebrities cheered for him.

But it was the public that embraced Captain Tom, flooding the village post office with some 6,000 gifts and 140,000 birthday cards. Moore marveled that anyone would spend 2 pounds ($2.74) on a card for him, and then put on a mask to wait in line at a post office to mail it.

He was made an honorary member of the England cricket team, had a train named after him, and was recognized with the Freedom of the City of London award. 

Moore enjoyed the accolades but remained focused on others.

He dedicated his autobiography, "Tomorrow Will Be a Good Day,'' to "all those who serve on the front line of any battle – be it military, psychological or medical.''

In the end, Captain Tom urged the public to look after one another, and he thanked the country he inspired for inspiring him.

"I felt a little frustrated and disappointed after I broke my hip and it knocked my confidence," he said after completing his trek. "However, the past three weeks have put a spring back in my step. I have renewed purpose and have thoroughly enjoyed every second of this exciting adventure, but I can't keep walking forever."