Garrett Sebesta, 15, was flown by helicopter to a Houston hospital for surgery after he was pulled from the water Monday afternoon.
Garrett's mother said her son was wading off the beach when he felt something bite his leg. He reached into the water to pull the shark off, and was bitten on the left hand.
Garrett has severe nerve damage in his hand and a chunk of his calf missing, but is expected to recover.
"He's gonna be good," said Z.W. Monnat, a paramedic who was one of the first on the scene. "Strong kid."
"Kudos to the victim, 'cause he felt the shark bite, and then he literally tore the shark off him," Monnat said.
A witness said Garrett was awake and talking when he was loaded onto a stretcher and then onto the Life Flight helicopter. Paramedics said he was airlifted so as to give him the best chance of retaining full use of his injured hand.
It was not immediately clear what kind of shark attacked him.