Olivia Strong set up a Run for Heroes 5km challenge that has encouraged a million people to run five kilometres, donate £5 and nominate five friends to do the same.
The Edinburgh fundraisers campaign “roused a global movement that has collectively run the entire distance to the moon and back”, the Prime Minister said.
Olympian Sir Mo Farah, singer Ellie Goulding and football coach John Terry are among the celebrities to take part.
Ms Strong said the idea to encourage people to use their daily exercise slot to raise money for health service charities came to her while she was on a run around Arthur’s Seat during lockdown.
The 27-year-old set out to raise £5,000 but the challenge soon spread.
Mr Johnson wrote to the fundraiser to thank her for coming up with the “brilliant” initiative.
He said: “As we persevere with the restrictions to stay at home, protect our NHS and save lives, I have been inspired by the ingenuity of your Run for Heroes 5km challenge.
“Using your daily lockdown exercise to run 5K, donate £5 and nominate five people, you have raised more than £5 million to support the extraordinary work of our true heroes – the men and women of our unique NHS.
“With over a million participants from more than 20 countries, you have roused a global movement that has collectively run the entire distance to the moon and back.
“Thank-you for your brilliant initiative and for all that you have done to support our wonderful NHS.”
The Prime Minister’s daily Point of Light award was first launched in April 2014 to recognise outstanding individuals making a difference where they live.
Ms Strong is the 1,363rd person to be recognised and follows Captain Tom Moore, who after raising £30 million for the NHS by walking more than 100 laps of his garden was named winner on Thursday – his 100th birthday.
Ms Strong said: “It’s an absolute pleasure and delight to accept this award on behalf of the whole Run for Heroes community.
“Not only the amazing people who have helped with the campaign but everyone who has continued to run, donate and nominate. It’s been so wonderful to see people coming together for such a worthwhile cause.”