The Australians wrapped up victory in the third over after lunch on the fifth and final day when Sri Lanka were dismissed for 410 despite a defiant 192 from Kumar Sangakkara, the highest score by a Sri Lankan in a Test against Australia.
The tourists resumed on 247-3, needing a further 260 runs to reach an unlikely victory target of 507, but lost six wickets in the extended morning session then their last batsmen 12 minutes after the restart.
Australian fast bowler Brett Lee, who was named man of the match in both Tests, captured four for 87 to finish with 16 wickets for the series.
The victory was Australia's 14th consecutive Test triumph, leaving them two short of the world record they set between 1999 and 2001, with a chance of setting a new mark in the upcoming home series against India starting on December 26.
"The end results probably say that this series has been easy win for us but there's a lot of hard work that goes into winning any Test match," Australia captain Ricky Ponting said.
"We played well in the first test in Brisbane and we carried a fair bit of that over into this game in Hobart.
"Once again, I thought our batting on day one and most of day two was absolutely outstanding and set the game up early and Brett led the way again with the ball."
Sri Lankan skipper Mahela Jayawardene conceded his side had been outplayed by a better team but could not hide his disappointment at losing the series 2-0.
"I felt we had a very good team, a good attack but the way we played wasn't very consistent," Jayawardene said.
"We couldn't penetrate that top order, which was very disappointing. And the way we batted was disappointing as well - particularly the first innings we played in both test matches.
"That gave us a lot of problems in the whole series. It's a very disappointing series."
Lee triggered the collapse when he made the initial breakthrough in the fifth over of the day, dismissing Sanath Jayasuriya for 45, caught behind by wicketkeeper Adam Gilchrist, diving to his left.
With their chances of winning all but over, Sri Lanka's hopes of at least salvaging a draw disappeared just three overs later when Mitchell Johnson captured two wickets in successive balls.
Chamara Silva was caught by Ponting at second slip without scoring then wicketkeeper Prasanna Jayawardene departed for a golden duck when he was trapped leg before wicket without offering a shot.
Sri Lanka helped contribute to their own downfall when Dilhara Fernando was run out for two, attempting a suicidal third run, before Sangakkara and Lasith Malinga staged a late fightback to ensure the tourists at least made it to lunch.
The pair put on 74 runs for the ninth wicket before Sangakkara was unlucky to be given out eight runs short of a deserved double-century, caught by Ponting off a bouncer from Stuart Clark even though television replays showed the ball ricocheted off the batsmen's shoulder.
"I think we all reacted on the two noises we heard at the time," Ponting said.
"I obviously caught the catch and appealed and went up for it and he was given out but he played beautifully today.
"I thought the way he struck the ball from about 120 onwards was some of the best hitting that you'll probably ever see with his back to the wall and running out of partners."