The cash will be distributed through the Steve Morgan Foundation to charities in Merseyside, Cheshire and North Wales.
Morgan, who founded Redrow in 1974, has also urged other entrepreneurs and philanthropists to do the same.
“The £1m per week will go into a war chest because we are at war against coronavirus,” he said.
“People who know me know I don’t like the limelight but now is not the time to hide in the shadows.”
The father-of-six made the decision despite seeing an estimated 50% wiped off his own fortune in the past month by the economic crash caused by Covid-19 but said it wasn’t important compared to the humanitarian crisis the world was facing.
He said: “Aside from the obvious difficulties that the charities are facing, supporting thousands of disadvantaged people, this crisis has already caused substantial cashflow issues. Normal day-to-day fundraising efforts that the charities undertake have been pulled from under them.
“The London Marathon alone puts around £65m into the charitable sector.
Morgan said that the foundation had already been approached by more than 50 charities desperately needed funding. One in just one day had 248 additional people register for their foodbank.
“As the economy shrinks it will be the charities and the vulnerable people who suffer first and we can’t allow that to happen.
“We wish we could help the whole of the UK but we can’t. Our Foundation is committed to helping charities in Merseyside, Cheshire and North Wales and we’ll continue to do that. We urge others across the UK to follow suit.”