He will piggyback his brother for 64km to raise awareness about cerebral palsy, a condition which afflicts the latter.
Hunter Gandee, 14, has been carrying his seven-year-old brother, Braden, "ever since he got too heavy for my mum".
"It's Braden's favourite form of transport," mother Danielle told ABC News.
And in what he is calling his Cerebral Palsy Swagger project, Hunter, an avid wrestler, is aiming to walk some 64km carrying his 27kg brother in a special sling.
Through the project, the Gandee family hopes research and technology will follow so new equipment to aid Braden and others with cerebral palsy will help them rather than hold them back.
The journey began at 8am (US time) yesterday with Hunter clocking 40km while walking from Bedford Junior High's wrestling room to the University of Michigan's wrestling room.
They will continue the remaining 24km of the journey today.
Hunter said he is "very protective" of his little brother.
"If he has any problems, I'm right there by his side," he said.
This article was first published on June 8, 2014. Get The New Paper for more stories.