Derrick Johns, his wife and daughter Erynn, 16, of Texas were swimming at Surfside Beach in Nantucket when the current pulled and tossed them.
Erynn was holding a video camera attached to a selfie stick when the current swept the family away.
The father-daughter duo gripped onto the selfie stick and Johns used the photo tool to pull Erynn towards the shore, where a man rushed to help her to safety.
"He was pretty far out still at that point when I got back and people were running in. There was a couple guys that ran in to try to get him out," she said.
Lifeguards and onlookers on the beach then rushed to help her parents.
"I did a few tours overseas with the Marines and I never felt that kind of fatigue or fear. I was semiconscious on the beach and when they put me in the truck they said my oxygen level was really low," Johns said.