But district judge Sam Goozee rejected his defence as 'implausible' and fined him £900 (NZ$1600), ordered him to pay £100 compensation to his victim and £500 costs.
The baby's family yelled "f*****g joke" as he was sentenced and confronted Hardy outside court yelling: "That sentence is disgusting. You punched a baby in the face. How do you sleep at night?"
Furious Ms Duckers said the sentence was "absolutely disgusting".
She added: "Basically, it means you can punch a five-day-old baby and all you will get is a £900 fine. It's sickening. The judge was satisfied he knew he was hitting a baby but then fines him. I'm literally gobsmacked.
"Hardy knew full well she was a baby. He admitted he'd come over to see a baby."
Elsie's grandfather John Duckers said that a fine instead of a jail term was "unbelievable for punching five day old baby."
He added: "He may as well have let him off with nothing. Accident or not that baby has been assaulted. It's disgusting I can't believe it. That's just one month's pay for him. Should have been a custodial sentence for him."
The judge who found him guilty admitted his doll defence was 'implausible', but rejected the chance to jail him for up to six months.
He said: "I find your explanation implausible. It was clear it was a baby and not a doll.
"It was strange and concerning behaviour and impossible to explain. Elsie was a vulnerable five day old baby. I accept that this was a exceptional case. I also accept that it was spontaneous, it lacked any pre meditation and I do believe it was completely out of character. The impact it had on Elsie's mother was clear."
Hardy had maintained that he though the child was a toy when he struck in Tesco.
The father of one Hardy, was with his wife Elaine who was beckoned over by a friend who said: "Come here and look at the beautiful baby".
Moments later Hardy punched five-day-old baby Elsie, who spent the next seven hours in hospital and suffered a mark on her head the size of an egg, the court heard.
He was arrested after the incident at the Tesco supermarket in Baguley on September 5 at around 6pm.
Elsie's mother Amy Duckers told magistrates today there was a loud 'slap' noise when 'he came rushing up and punched her in the face".
She added: "I said 'you have hit my baby' and he said 'no I didn't'." before heading off down the biscuit aisle.
District judge Sam Goozee was told that Hardy approached five day old Elsie as she lay in her carry cot inside a shopping trolley then thumped her as the youngster's mother Amy looked on in horror.
The baby who was left in tears with a red mark to her face, was taken to hospital and was kept in for seven hours before being allowed home.
The incident went viral across social media after Miss Duckers, a 27-year old carer, relayed it on Facebook and branded the perpetrator as "sick, twisted and vile".
The prosecution said: 'Amy was shopping in Tesco with her family, her partner Lewis Temple, daughter Libby Brown and new baby Elsie Temple.
