Healy's belligerent 138-ball innings, the highest total in a World Cup final, helped Australia set a mammoth victory target of 357 at Hagley Oval which proved well beyond England despite a fighting century by Nat Sciver.
Sciver's unbeaten 148 entertained the crowd but she lacked support from her top order colleagues, and England were bowled out for 285 with six overs to spare.
"That was pretty special from our group," said Healy, who was carrying a back injury.
"It was something we've been working on for a very long time.
"Full credit to the bowlers, they held their nerve ... It was just a good game of cricket."
Leg-spinner Alana King took 3-64 after pace bowler Megan Schutt (2-42) did the early damage by removing both England's openers.
Favourites Australia finished the tournament unbeaten in nine matches, erasing their 2017 World Cup disappointment when they were stunned in the semi-finals by India in England.
The peerless Australians have now won three of the last five 50-over World Cups and won both the major global trophies, having claimed the T20 World Cup on home soil in 2020.
Four days after smashing 129 in the semi-final against West Indies, wicketkeeper-batter Healy blasted 26 fours as Australia posted 356 for five, sent in to bat after England won the toss.
Healy anchored 100-run partnerships with fellow opener Rachael Haynes (68) and number three Beth Mooney (62).
She cut seamer Anya Shrubsole for a single to bring up her fifth ODI century, yelping in delight as beaming husband Mitchell Starc, the Australian men's fast bowler, clapped in the crowd.
She was finally stumped by Amy Jones off Shrubsole and strolled off to a standing ovation at 316 for two, having again burnished her record as the ultimate big-game performer.
Two years ago, she hammered a 39-ball 75 to guide Australia to a big win in the T20 World Cup final against India at the Melbourne Cricket Ground.
Barring a few testing overs from the seamers at the start, it was a poor day in the field for Heather Knight's England.
Seamer Kate Cross was let down twice in four balls by her teammates, with Haynes dropped for 47 and Healy for 41.
Healy was later dropped on 136 at short fine leg by a leaping Beaumont after trying to ramp Sciver.
Soon after, she smashed three consecutive fours off the hapless Ecclestone, the first lofted boundary over the covers bringing up her 150 in one of the great World Cup knocks.