She was seeded seventh in this tournament.It also makes her the first German woman to win the Australian Open since Graf in 1994 and the first German to win a Grand Slam since Graf's final win before retiring in 1999 at the French Open.
German Chancellor Angela Merkel was quick to send congratulations.
"With this victory you have not only fulfilled your own biggest dream but also, once again 17 years after Steffi Graf, the hopes of millions of tennis fans of a German winning the Grand Slam tournament," Merkel said in a statement.
"It was fascinating to see how courageously and, with such nerves of steel, how you prevailed in the final against arguably the best player in the world. I hope you will enjoy the victory fully and then go on to many more successes."
Heading into the Australian Open, the big question was whether anyone could beat Williams, the defending champion going for her seventh win at Melbourne Park. A few names were tossed around, but not Kerber's.
Kerber had been in the Top 10 for four years and her best result at a major was the semifinals at 2012 Wimbledon and 2011 U.S. Open.
Last year, she lost her first-round match in Melbourne and came close to repeating it this year when she saved a match point in her first-round win over Misaki Doi.
"When I played here the first round I was match point down so I was actually with one leg in the plane to Germany and now I'm here," Kerber told the crowd in the 15,000-seat Rod Laver Arena, which started out supporting Williams and quickly switched.
That close call made Kerber feel she had nothing to lose. And that's how she played Saturday night in the biggest match of her life.Williams was not at her best. But Kerber chased everything down, ripped ferocious cross-court winners and took a lot of risks.
In the sixth game of the third set, which went over 10 minutes, she was a game point down and produced a beautiful backhand drop shot from the baseline that drew roars and applause. And a few points later, she did it again before breaking Williams to take a 4-2 lead.Throughout the tournament, Kerber has talked about advice she received from Graf, her childhood idol who is now a mentor.
Last year, she got to play some rallies with Graf during a visit to Las Vegas, where Graf lives with her husband Andre Agassi and their two children. Graf told her she was good and headed in the right direction, and to try to believe in herself - a mantra she kept repeating in her head, Kerber said.
The mental conditioning paid off."I think I helped Steffi right now," she said smiling, when asked about preserving Graf's record.
"Steffi is a champion. She won 22 Grand Slams. That's my first one... The hard work pays off."Graf sent her a text message before the final to wish her luck.
And there was another one waiting in her phone Saturday night, along with many, many others."I think my phone is exploding right now. I don't know how many messages I got," Kerber said. But the phone's battery died soon after her big win, so she couldn't immediately see what Graf said.
"I was just able to call my mom, my parents, my grandparents, and that's it," Kerber said. "So I have no idea."
- AAP