It is something he has been able to do for only a matter of weeks.
As his mother Bex picks him up to carry him outside, he protests.
"No, I want to walk."
Determined, he walks the rest of the way out the door helped again by his mother.
The family returned to their Dunedin home on Friday, after Harry underwent surgery performed by Dr Tae Park, at the St Louis Children's Hospital, in the United States, which could, one day, help him to walk unaccompanied.
Harry was born with spastic diplegia cerebral palsy which made his legs move in a scissor motion.
The operation was to release the muscle tension in his legs.
His father Hayden said Harry could walk with assistance "straight away" after the removal of his casts two weeks ago.
He is excited to test his new ability.
"He's so determined to try and walk. He wants to try and walk everywhere."
Harry now faces seven years of visiting the physiotherapist four times a week for strength building and his parents must help Harry stretch each leg 100 times every morning and night.
"They are basically at baby strength at the moment."
At the weekend, Harry smiles, waves and insists on bouncing on the trampoline.
It is a brave attitude from a boy who only last month lost a lot of weight in hospital, developed a bad rash from an epidural and barely ate for a week.
A high point of the trip for the family was finally meeting Dr Park, who plans to visit Harry early next year.
Mr Finch said the surgery also improved the motion in Harry's arm, meaning he could "put his arms right up to hug you properly".
They dream of him standing unassisted within a year.
"That's to make me walk," Harry said, pointing to a fundraising wristband worn by his mother.
The family raised more than $150,000 needed for the surgery, but have ongoing costs of up to $20,000 annually.
It is likely to be many years before Harry can walk on his own.
Mrs Finch said the hardest part of the last few weeks was watching her boy endure so much pain.
But you would not know it, as he cheerily farewells you, a big grin on his face, and says "Bye, thank you for coming".
