Having led 21-3, the All Blacks - reduced to 14 men when Ben Smith was shown yellow 12 minutes into the second half - saw their fierce rivals close to within four points thanks to tries from David Pocock and Tevita Kuridrani. However, a drop goal and penalty from Dan Carter eased any New Zealand nerves, before Beauden Barrett went over to seal a historic triumph.
New Zealand dominated from the off but saw their point-scoring opportunities limited by a dogged Australian defence. After Carter had opened up a 9-6 lead with the boot, Nehe Milner-Skudder eventually broke the Wallabies' resolve by going over in the closing stages of the first half.
Ma'a Nonu - one of a host of All Blacks making their last Test appearance - sprinted for the line to further dent Australian hopes shortly after the interval, but Pocock's try after Smith had been sent to the sin bin offered a glimmer of hope. Kuridrani's subsequent touchdown put the All Blacks on edge but Carter and Barrett clinched the win - a fitting swansong for those players who have worn the All Blacks jersey for the last time, a group that could include Carter and captain Richie McCaw.
The All Blacks had never won a World Cup on foreign soil but demonstrated their power early on, although a rousing rendition of Swing Low, Sweet Chariot demonstrated just how many neutrals were in attendance at Twickenham.
Carter - playing in his first final - got New Zealand off the mark when their pressure yielded a penalty after eight minutes, but a careless Smith knock-on afforded Australia their first chance to get points on the board. Bernard Foley took full advantage from 25 metres out to restore parity.
Few could question that the All Blacks had looked most threatening early on, and Carter edged his side in front again with a 27th-minute penalty. Steve Hansen's men enjoyed increasing opportunities to stretch their legs as the half progressed - Australia shorn of injured pair Kane Douglas and Matt Giteau - and Carter was on target to stretch the lead to six four minutes from the break.
New Zealand's pressure was finally rewarded before referee Nigel Owens blew for half-time, Milner-Skudder diving over in the corner after the All Blacks found themselves with numbers out wide - Carter adding the extras.
Australia needed to come out fighting in the second half but slipped further behind when Nonu found a gap in the Australian defence and ran almost half the length of the pitch to touch down. Carter missed with the conversion and, as the game started to open up, Smith was awarded a yellow card for an apparent tip tackle on Drew Mitchell.
Australia made their numerical advantage count immediately as the ever-impressive Pocock emerged from the back of a driving maul to power over, with Foley moving his side into double figures from the tee.
Momentum was now with the Wallabies and Kuridrani crossed the whitewash after Foley found space behind the New Zealand line - the latter's conversion pulling Australia within four.
But that was as good as it got for the Wallabies, with Carter kicking six more points before Barrett demonstrated his football skills to clinch a record third title for the All Blacks late on.