But six months ago, the toddler couldn't sit up by himself, nor crawl or speak.
After a traumatic, premature birth, the 22-month-old from Papua New Guinea developed a rare growth on his head the size of a small football.
He was well but developmentally delayed.
His desperate mother sought help and the Children First Foundation arranged Ivan-Joe's passage to Australia to treat his rare condition.
The medical team at Monash Children's Hospital in Melbourne performed complex surgery, offering a humanitarian bed at no cost and medical help pro-bono.
Neurosurgeon Chris Xenos said Ivan-Joe now has a better shot at life.
"He's a lot more vocal and a lot more mobile. He doesn't stop now," he told reporters at the hospital on Tuesday.
Ivan-Joe's treatment involved inserting a shunt tube to drain fluid from his head into his stomach, then sealing his brain and rebuilding his skull.
The second, more complex operation took more than eight hours and a big team of surgeons.
Dr Xenos said Ivan-Joe had made neurological improvements since the surgery.
"It means hopefully he can fulfil all his potential as he grows up because there's no longer pressure in his brain from excess fluid and that defect has also been repaired," he said.
Ivan-Joe is ready to return home with his mother on August 30.
Doctors are optimistic about his future.
"If this lump were to continue to have gotten bigger and the pressure had built up in his brain, I would've been concerned about further neurological delay," Dr Xenos said.
Joselyn Leo realised something was wrong soon after giving birth.
She spoke of the cruel taunts by other children that her baby had two heads.
"I'm very grateful for what they have done for my son," Ms Leo said, wiping away tears.
"Now he's a normal child.
"The surgery was like a miracle."
LIFE-CHANGING SURGERY FOR TODDLER IVAN-JOE LEO:
- Ivan-Joe was born with an encephalocele, a complex craniofacial abnormality
- The abnormality caused fluid to collect on the top of his head
- Monash Children's Hospital surgeons inserted a shunt to drain the fluid away
- Ivan-Joe was left with a crater on his head until a second, more complex surgery was performed three weeks later to reshape his head.