The 20-month-old victim was outside a DoubleTree by Hilton hotel with his mother on the morning of October 2, when he was mauled by the dog as it was walked by owner Thomas Ackah.
The toddler had reportedly been staying at the four-star hotel in Catherine Grove with his mother and his father, a Dutch businessman visiting London for work.
The boy's father was working when the attack happened, but described the incident as "shocking and horrific".
"My wife and son were about to go for breakfast and my son was walking around the steps to the hotel when the dog came out of nowhere and attacked him," the father, who was not named, told MailOnline.
He said the dog "latched on" to his son's thigh, leaving multiple puncture wounds.
Photos taken in the aftermath appeared to the show the boy's mother shielding him as Ackah, tried to restrain the dog.
"My wife managed to get in the way of the dog slightly to shield our son," the father told MailOnline. "If she hadn't done that, it could've been much worse."
The child reportedly needed surgery, and was discharged from hospital after two days. Police described his injuries as "not life-threatening or life-changing".
Ackah, of the Old Kent Road in Bermondsey, was charged by police with allowing a dog to be dangerously out of control.
The dog was later found to be an American XL Bully, described as "apricot-coloured".
It was put down, with Ackah's permission.At Bromley Magistrates' Court on October 3, Ackah pleaded guilty to 'being in charge of a dog dangerously out of control, causing injury'.
On Monday, he was sentenced to 10 months in prison, disqualified from having custody of a dog for five years, and ordered to pay a victim surcharge of £187.
It came after prime minister Rishi Sunak last week announced American Bully XLs are to join the government's list of banned breeds under the Dangerous Dogs Act, from the end of 2023.
The new laws will make it illegal to "breed, sell, advertise, exchange, gift, rehome, abandon or allow XL bully dogs to stray" in England and Wales from December 31.
The dogs must also be kept on a lead and muzzled in public from that date.From February 1, 2024 , it will then become illegal to own an XL Bully if it is not registered on the Index of Exempted Dogs.
Owners without a certificate of exemption from that date would face a criminal record and an unlimited fine, and their dog could be seized.