Michael Bedford, 40, was surfing at remote Conspicious Cliff beach when the shark knocked him off his board and circled round before charging at him for a second time.
He managed to punch the animal and get back on his board, catching a wave to the shoreline despite suffering a gash in his leg.
He was then hauled up the beach by his friend Lee Cummuskey and a group of local fishermen, using his surfboard as a stretcher and a surfboard rope as a tourniquet.
Mr Bedford had a "pretty horrendous wound" on his right leg, according to witnesses.
The father-of-two is in a stable condition in hospital.
He told the West Australian newspaper he is "eternally thankful" to those who helped him and that the attack was so quick, he had not realised he had been bitten.
Local tourism operator Mr Cummuskey was waiting for his friend on the beach when he saw the attack take place.
He said: "Bang, I saw the hit, I didn't really see the fish... I could just see this explosion of water and I knew straight away what had happened."
Mr Bedford punched the shark, which is believed to be a great white, twice before escaping.
"He gave it a good whack he reckons, a good punch and that doesn't surprise me knowing Mick," Mr Cummuskey told ABC news.
"It is your worst nightmare and Mick's been through it and survived so he's just really lucky."
