He made the decision at a High Court hearing in London during the latest stage of a legal dispute between Charlie's parents and London-based doctors.
The 11-month-old boy suffers from mitochondrial depletion syndrome, a rare genetic disease that has left him brain-damaged and unable to breathe unaided.
But days afterward, President Donald Trump and Pope Francis gave the parents new hope by shining an global spotlight on the ethical debate.
Gard's parents have raised more than £1 million to take their son to the United States to receive the treatment, which Hirano believes could have an 11% to 56% chance of muscular improvement.
After a series of hearings and appeals in several courts, the European Court of Human Rights decided on June 30 that the hospital could discontinue life support to Charlie and he could not be transferred.
But journalists have argued naming Dr Hirano will be in the public interest - and he has now said he has no objection to being identified as the doctor involved in the case. The guardian was "arguing in open court in the second highest court in Great Britain that Charlie's parents should not be at [these meetings] Monday and Tuesday".
In addition to evaluating Charlie next week, Hirano will meet with doctors and others who have been caring for him.
Officials at Great Ormond Street Hospital in the United Kingdom, who have recommended that life support for 11-month-old Charlie Gard be withdrawn so that he dies, now have tried to exclude his parents from a meeting that could very well decide his future.More news: Gallery-Goer Loses Balance, Knocks Over So Many Pedestals Of Art
Hirano claimed that he could treat Gard with at least a 10 percent chance of improving his condition, according to Lifesite News.
On Thursday, Chris Gard and Connie Yates, Charlie's parents, walked out of a British courtroom after arguing with the judge, but returned later in the day.
They have new hope this morning after the High Court in Strand, London, was told by Dr Hirano on video link that in fact there is a small chance of improvement. The judge offered a reassuring word, acknowledging that the situation was desperate.
"He's our own flesh and blood and we don't even have a say in his life whatsoever", Yates said.
The courts have been relucant to allow Charlie to go because judges so far have concluded that this would only prolong his suffering and there is no realistic chance of him getting better. "If he was we wouldn't be up here fighting for that".
In a reflection of the tension surrounding the case, Chris Gard and Connie Yates stormed out mid-hearing when they disagreed with remarks by the judge.
Connie and Chris, from west London, hope the new information will convince Mr Justice Francis to let them take Charlie to America.
"We have letters and invitations from doctors and specialists from around the world and medical evidence that shows that Charlie could greatly benefit from this ground-breaking treatment".
A petition is circulating concerning Charlie's condition, with just under 500,000 signatures, at Citizengo.org. The hospital believes his life support systems should be turned off.