Witness Robert Lee said he and his wife were on their way to a furniture store when they saw the accident on a road in League City, a suburb of Houston, Texas.
"We heard a loud boom that caught our attention. You couldn't miss it," Lee told our sister station KTRK.
Lee, who is recently retired from the U.S. Coast Guard, said he felt a rush of adrenaline and jumped on top of the vehicle.
Once he saw that the passengers didn't need immediate medical attention, he opened the vertically-facing side door and began to help them out.
He said before he knew it, an entire group of people jumped in to lend a hand.
Together, Lee and the other good Samaritans pulled the five family members out of the flipped truck, including two young children and the family's Great Dane.
"It was just a blessing to see everyone come together," Lee said. "I'm real proud to live where I'm at."
Lee said all members of the family were OK after the accident.