About 80,000 works of art, ceramics, manuscripts, letters and photographs faced being auctioned to help pay off the pottery firm's pension debt.
But a public fundraising campaign launched in September hit its target in just a month.
Adminstrators Begbies Traynor said the collection will remain on display at the museum in Barlaston, Staffordshire.
The Art Fund, which led the campaign, will gift the collection to the Victoria and Albert Museum, before it is loaned to the Wedgwood Museum.
Administrator Bob Young said it had been "incredibly satisfying" to sign off on the sale on Monday.
"Today's fantastic outcome wouldn't have been possible without the spirit of goodwill and determination shown during the often complex negotiations," he said.
The Wedgwood Museum inherited Waterford Wedgwood plc's pension bill after the firm collapsed in 2009.
In 2010 the museum also went into administration, and in 2011 a high court judge ruled its collection could be sold to reimburse the Pension Protection Fund.
Alison Wedgwood, whose husband Tom is a direct descendant of company founder Josiah Wedgwood, said the collection was "important" for Staffordshire.
The collection risked being "sold and scattered around the globe" had the money not been raised, she added.
Tristram Hunt MP, who was involved in the campaign, said the sale was "fantastic news".
"The items contained within the Wedgwood collection chart a significant part of Britain's cultural development over centuries and play a crucial part in defining our national identity today," he said.

Anderson, level with Darren Gough on 234 before the game, took the wicket of Mitchell Marsh to move past the former Yorkshire seamer's old record.
The Lancashire seamer's record-breaking wicket came in the first ball of his seventh over at Edgbaston.
He went on to take his new record to 237 with two more wickets.
Six others have taken 100 ODIs wickets or more for England, but only Anderson and Gough have broken the 200 barrier.
Sri Lanka spinner Muttiah Muralitharan holds the world record with 534 wickets from 350 matches, while Pakistan pace bowler Wasim Akram took 502 from 356.
Anderson is 25th in the all-time world list but has only played 170 internationals.
The 30-year-old became only the fourth England player to take 300 Test wickets when he dismissed New Zealand opener Peter Fulton during the first Test at Lord's in May.
If he is to become England's most successful Test bowler of all time, he will have to overhaul Sir Ian Botham's 383, with Fred Trueman's 307 and Bob Willis's 325 his next targets.
In February of this year, Anderson claimed his 529th scalp in all formats to pass Botham's 528 and become England's leading international wicket-taker.
"He's right up there with the best that England have had and he's right up there with the best in the world," said former England captain Michael Vaughan last month.

More than 1,000 drivers and engineers were set to stage the walkout on Bank Holiday Monday in a dispute over rosters.
It was supposed to be the second day of strike action after Unite members at Tower Transit took action on Friday.
It said it decided to suspend Monday's industrial action after "solid support" for Friday's protest.
A spokesperson said it wanted to give the company time to "reflect and respond".
Transport for London said Tower Transit operated less than 5% of the bus network.
The Wedgwood Museum collection has been bought from administrators after £15.75m was raised to save it.
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James Anderson became England's leading wicket-taker in one-day internationals with his 235th victim as they
[NEXT_CONCEPT]
A planned bus drivers' strike which threatened to disrupt Notting Hill Carnival has been called off.