In one of the most lop-sided deciders ever, the American utterly dominated third seed Safina, allowing her opponent to win only eight points in the first set on her way to claiming the championship in less than an hour.
"I'm so excited ... I clearly love playing here and I get great support here. I don't get that every place I go," she said after winning the first women's night final played in the Rod Laver Arena.
Williams, the second seed, emphatically backed up her pre-tournament comments that she was the best women's tennis player in the world and will now officially reclaim the top ranking from Serbia's Jelena Jankovic.
She also became the highest ever prize money winner in women's sport during the tournament and won the women's doubles title with her sister Venus on Friday.
Williams said she was thrilled to join the likes of Steffi Graf and Martina Navratilova in the elite group of women with 10 or more Grand Slams.
"I idolised Steffi Graf," she said. "When I played her I was like 'Oh My God, it's Steffi Graf' and Martina Navratilova was someone who was my role model, so when I think of these greats I don't really think of my name, I think of them.
"I think people are starting to think of me (in those terms), which is uber-cool, I can't even get my mind around that."
Safina, whose brother Marat Safin won the men's title in 2005, had aimed to enter the history books as the part of the only brother-sister combination to hold Grand Slam titles.
Instead, she narrowly avoided entering the record books as being on the wrong end of the worst drubbing in a final in the tournament's history.
"Serena was too good, I was only a ball boy on the court today," the 22-year-old Russian said.
"Sorry to the people who supported me, today I let you down a little bit but I'll come back next year and try and do better."
Only Graf in 1994 and Margaret Smith in 1962 have posted more comprehensive victories in the decider, both winning 6-0, 6-2.
Williams continued a sequence of winning the Australian Open title in odd-numbered years, with her previous wins coming in 2003, 2005 and 2007.
Safina also lost her only previous Grand Slam final at the French Open last year but Williams was full of praise after the match.
"Dinara has a good future," she said. "She's hitting the ball so hard I just had to go for broke.
"Thanks to her for putting on a great show for women's tennis."
The Russian may take some comfort from compatriot Maria Sharapova, who also managed to take just three games off Williams when she was humbled 6-1, 6-2 in the 2007 final but came back to take the title the following year.
Williams showed no signs of the service problems that dogged her early in the tournament and aggressively took the game to Safina from the outset.
It was Safina's serve, with its trademark high ball toss, which fell apart as she coughed up three double faults in her opening service game to gift Williams an easy break.
She continued to break Safina at will, while the Russian could only manage two points off Williams' serve in a first set that that was over in 22 minutes.
"I saw that it was so fast and I thought okay I've got to stay focussed," Williams said.
"I thought 'Safina, she's a warrior, she never gives up, she's been down a couple of match points already in the tournament, so I've got to stay focussed."
Safina desperately tried to regroup and broke Williams in the first game of the second set but could not stop the rout and conceded the match when she hit a drop shot wide after 59 minutes.