England collapsed in humiliating circumstances to hand Australia a comprehensive 281-run victory and the third 5-0 clean-sweep in Ashes history.
After England won 3-0 to secure the urn for a third consecutive series in the UK last year, Australia have answered four months later with the most emphatic turnaround imaginable.
Set an improbable target of 448 to win in Sydney after another Chris Rogers century, England were all out for 166 late on Sunday.
When Harris took the last wicket of Boyd Rankin to complete a five-wicket haul, the Australians converged in a huddle in front of a packed house and Nathan Lyon led an early rendition of the team song.
"5-0 how about that," said Harris.
"The feeling in Perth was unbelievable but to clean sweep a series, far out how good is it.
"We wanted to make sure we kept it going the whole series and we did ... it's amazing we were able to do that and keep the faith of selectors.
"It's different (singing the team song on field). It's what Lyno wanted, it's what we do. We're going to enjoy this I'll tell you now."
Johnson (3-40) took two wickets in the over after tea, to bring his personal tally to 37 scalps for the tour and pave the way for pace ally Harris (5-25) to do the rest.
With more than two days left in the match, England surrendered meekly, with their three best batsmen Alastair Cook (7), Ian Bell (16) and Kevin Pietersen (6) rolling over to leave the tourists precariously placed at 3-87 at tea.
Any hope of England showing fight and taking the game into a fourth day were dashed when they lost 4-8 in 17 balls at the hands of Johnson and Lyon after tea.
Australia won 5-0 in 1920-21 and 2006-07, but the charge led by Michael Clarke's men was arguably the most ruthless of all.
It's the first time Australia have taken all 100 wickets in a five-match Ashes series, and they maintained an unchanged XI from start to finish, for the first time ever in five matches, to do it.
Johnson and wicketkeeper Brad Haddin have been the runaway stars for Australia.
The left-arm fast bowler went from enigma to unstoppable force by taking the most wickets by an Australian fast bowler in a five-match Ashes series, placing him ninth on the all-time list.
Haddin was another who not so long ago thought he'd played his last Test - only to defy his 36 years and save Australia on countless occasions.
The wicketkeeper finished second on the run-scoring list, scored a half century in every first innings of the series and became the fourth Australian gloveman to score 3000 Test runs, joining Ian Healy, Rod Marsh and Adam Gilchrist.
Rogers, also 36, wound back the clock with his third Test century and second in consecutive matches.
Born in Sydney 36 years ago, Rogers continued his remarkable career renaissance by smashing his fastest on in 143 balls as Australia were all out for 276 soon after lunch.
Australian skipper Clarke admitted not even he thought 5-0 was possible after the horrors of last winter.
"Probably not 5-0 ... This series is an indication that the hard work guys have put in over last 12 months has paid off.
"The fast bowlers have done a fantastic job. I had a brief conversation before the first Test and said to those guys, tha in my opinion they were the best attack in the world. Nathan lyon complements that and I think they've earned that mantle."
England captain Cook said his team were simply outplayed, before going over to thank the Barmy Army supporters.
"Obviously we weren't good enough to turn it around," he said.
"We tried to talk about it, change the way we played. Credit to Michael and his team - anything we threw at them they responded. They thoroughly deserved their 5-0 win.
"When you hit rock bottom the only way is up. It happened in 06-07 and we turned it around.
"We need to look at ourselves and where we want to go. We know we have a huge amount of talent in England - we haven't showed it this series.
"Thanks to all the supporters, sorry we've let you down."
AUSTRALIA FIRST INNINGS
C ROGERS b Stokes 11 (39)
D WARNER b Broad 16 (20)
S WATSON lbw Anderson 43 (59)
M CLARKE c Bell b Stokes 10 (29)
S SMITH c (sub) b Stokes 115 (154)
G BAILEY c Cook b Broad 1 (8)
B HADDIN c Cook b Stokes 75 (90)
M JOHNSON c (sub) b Borthwick 12 (32)
R HARRIS c Anderson b Stokes 22 (27)
P SIDDLE c Bairstow b Stokes 0 (1)
N LYON not out 1 (3)
Sundries (10b 2lb 2w 6nb) 20
Fall: 22 (Warner), 51 (Rogers), 78 (Clarke), 94 (Watson), 97 (Bailey), 225 (Haddin), 269 (Johnson), 325 (Harris), 325 (Siddle), 326 (Smith).
Bowling: J Anderson 21-3-67-1, S Broad 19.5-5-65-2 (2w), B Stokes 19.5-1-99-6 (5nb), B Rankin 8.2-0-34-0 (1nb), S Borthwick 7-0-49-1.
Batting time: 355 mins. Overs: 76.
ENGLAND FIRST INNINGS
A COOK lbw Harris 7 (19)
M CARBERRY c Lyon b Johnson 0 (9)
J ANDERSON c Clarke b Johnson 7 (24)
I BELL c Haddin b Siddle 2 (32)
K PIETERSEN c Watson b Harris 3 (9)
G BALLANCE c Haddin b Lyon 18 (51)
B STOKES b Siddle 47 (101)
J BAIRSTOW c Bailey b Siddle 18 (50)
S BORTHWICK c Smith b Harris 1 (17)
S BROAD not out 30 (22)
B RANKIN b Johnson 13 (22)
Sundries (1lb 5w 3nb) 9
Fall: 6 (Carberry), 8 (Cook), 14 (Anderson), 17 (Pietersen), 23 (Bell), 62 (Ballance), 111 (Bairstow), 112 (Stokes), 125 (Borthwick), 155 (Rankin).
Bowling: R Harris 14-5-36-3, M Johnson 13.5-3-33-3 (1w/5 3nb), P Siddle 13-4-23-3, S Watson 3-1-5-0, N Lyon 15-3-57-1.
Batting time: 267 mins. Overs: 58.5.
AUSTRALIA SECOND INNINGS
C ROGERS c & b Borthwick 119 (169)
D WARNER lbw Anderson 16 (20)
S WATSON c Bairstow b Anderson 9 (9)
M CLARKE c Bairstow b Broad 6 (18)
S SMITH c Cook b Stokes 7 (12)
G BAILEY c Borthwick b Broad 46 (74)
B HADDIN b Borthwick 28 (40)
M JOHNSON b Stokes 4 (3)
R HARRIS c Carberry b Borthwick 13 (10)
P SIDDLE c Bairstow b Rankin 4 (6)
N LYON not out 6 (10)
Sundries (14lb 2w 2nb) 18
Fall: 27 (Warner), 47 (Watson), 72 (Clarke), 91 (Smith), 200 (Bailey), 239 (Haddin), 244 (Johnson), 255 (Rogers), 266 (Harris), 276 (Siddle).
Bowling: J Anderson 15-6-46-2, S Broad 14-1-57-2 (1w 2nb), B Rankin 12.3-0-47-1, B Stokes 10-0-62-2 (1w), S Borthwick 6-0-33-3, K Pietersen 4-1-17-0.
Batting time: 283 mins. Overs: 61.3.
ENGLAND SECOND INNINGS
A COOK c Haddin b Johnson 7 (12)
M CARBERRY c Haddin b Johnson 43 (63)
I BELL c Warner b Harris 16 (19)
K PIETERSEN c Bailey b Harris 6 (10)
G BALLANCE lbw Johnson 7 (27)
B STOKES b Harris 32 (16)
J BAIRSTOW c Bailey b Lyon 0 (3)
S BORTHWICK c Clarke b Lyon 4 (2)
S BROAD b Harris 42 (36)
J ANDERSON not out 1 (1)
B RANKIN c Clarke b Harris 0 (2)
Sundries (5b 2lb 1nb) 8
Fall: 7 (Cook), 37 (Bell), 57 (Pietersen), 87 (Carberry), 90 (Ballance), 91 (Bairstow), 95 (Borthwick), 139 (Stokes), 166 (Broad), 166 (Rankin).
Bowling: R Harris 9.4-4-25-5, M Johnson 9-1-40-3 (1nb), P Siddle 4-1-24-0, N Lyon 9-0-70-2.
Batting time: 145 mins. Overs: 31.4.
Umpires: Aleem Dar (PAK), Marais Erasmus (RSA).
Match Referee: Ranjan Madugalle (SRI).
Third Umpire: Tony Hill (NZL).
Result: Australia won by 281 runs
Series: Australia won the 5-match series 5-0