The horse, trained by Mouse Morris and owned by Ryanair boss Michael O'Leary, was paraded through the streets of Mullingar, County Westmeath, on Sunday.
The 33-1 shot won the Aintree race on Saturday and returned to Ireland on an overnight ferry.
Traffic was stopped as the horse made his way up Mullingar's main street.
Mr O'Leary said: "We don't bring enough trophies here to Mullingar, and on the rare occasion when Tipperary and Mouse lend us one I think we should bring it down here and let the people in Mullingar celebrate."
On Saturday, Mr O'Leary said he would "like to retire" the nine-year-old horse "if the trainer will let me".
Hundreds of people have turned out to greet Grand National-winning horse Rule The World on his return to the Republic of Ireland.