The retailer, which sells more than 10 million eggs a week, said it has moved to a fully free-range supply five years ahead of previous plans.
In 2016, the Bradford-based business said it would end the sale of caged eggs by 2025 following a consumer campaign by teenager Lucy Gavaghan.
It has now beaten its initial target after doubling the number of farmers the firm works with an increasing egg supply at its own manufacturing site.
The supermarket chain is the first of the big four supermarkets to start using only free-range eggs, with Sainsbury's set to stock 100% free-range eggs from April.
Other rivals such as Co-op and Waitrose already sell only free-range eggs in their stores.
Morrisons said the commitment will mean that all of its eggs will come from hens that have outdoor access for at least eight hours each day, as well as nest boxes.
The group said it will also ensure that all the eggs used as ingredients in its products will be from free-range from 2025.
Morrisons is also dropping the price of a pack of six free-range eggs from 80p to 75p.
Robert Hofmann, egg buyer at Morrisons, said: "Improving animal welfare is very important to customers and it's very important to us.
"We source our eggs directly from farms and have worked hard to help them all move to free-range.
"From today, all our eggs will come from free-range hens that are able to roam freely outdoors - typically during daylight hours - and then return to nest boxes in the evening."
Dr Tracey Jones, director of food business at Compassion in World Farming, said: "It's great to see Morrisons achieving their commitment to be 100 per cent free-range on shell eggs ahead of their target.
"Momentum on ending the use of cages for laying hens is growing and Morrisons are leading the way."