Decked out in a wetsuit, the 47-year-old Sydney native pulled the arm of a man later identified as Peter Adam, who said he was helping the actor's 10-year-old daughter, Ava Jackman, reach a sandbar, reported 9news.Com.Au.
He later fought crashing waves to reach Oscar, gesturing wildly at others who had wandered farther out into the tide.
The "Wolverine" star's representative later said he and his son were "100 per cent fine."
Jackman wasn't the only hero on the beach that day - lifeguards also jumped on boards and jetskis to rescue "several" other swimmers.