Geale, 31, won easily on all the judges’ scorecards after 37-year-old Mundine went the distance.
Geale lost a controversial split decision against Mundine in 2009 – his one loss in 30 fights, including that on Wednesday night. However he was dominant throughout their latest meeting, setting the tone with a destructive left body shot then left hook to his opponent’s cheek early on.
"Anthony came prepared and gave me a hard, hard fight," Geale said.
"I came here wanting to do well. I hope you guys enjoyed it. It was enjoyable tonight, I enjoyed punching him."
Mundine’s one hope of the knockout he needed came in the eighth, when he landed a huge right – but Geale survived.
Mundine – who was warned after a clash of heads in the third – had not fought anyone of note in recent times, while Geale defeated Felix Sturm, Osumanu Adama, Eromosele Albert, Sebastian Sylvester and Roman Karmazin.
Mundine’s record is now 44-5 (26 KO). Fifteen of Geale’s wins have come by way of knockout.
On the undercard American street-fighting legend Kimbo Slice knocked out Australian Shane Tilyard two minutes into the second round to stay unbeaten after seven professional bouts.
Slice was decked in the first round, but came back in the one following with a body shot.