Daniel Braxton was driving through Towyn, Conwy county, with his 18-year-old daughter at 07:15 BST on Tuesday.
She thought she saw a dead baby in the bus stop near the Magpie and Stump pub and screamed at her father to drive back to check, which he did.
Mr Braxton, 35, said he saw the lifeless naked baby on the ground, with her umbilical cord still attached.
"We blocked the road off and rang the emergency services," he told BBC Radio Wales.
"I had a dressing gown in the car and ran to grab that, wrapped the baby up, gave her some good hard rubs on the chest and the head.
"She took one big gulp of breath and opened her beautiful little eyes."
Mr Braxton, who is originally from Birmingham and living in nearby Pensarn, said they guessed that the baby was less than one hour old.
"To be honest, I think the fatherly instinct and the adrenaline kicked in because my daughter was hysterical and my partner was hysterical," he added.
"So it was just a case of as soon as I saw her lying there, her naked little body just left on cold concrete, I knew something had to be done."
Mr Braxton said police have told him that the baby has "stabilised and is on her way to a full recovery".
Police are concerned about the welfare of the baby's mother and have urged her to come forward.
Helen Douglas, of North Wales Police, said: "We are concerned about the health of the mother of the baby girl and are appealing for her to come forward.
"Alternatively, if anyone knows who the mother is or can provide any information which may assist in identifying her please contact North Wales Police.
"We want to ensure that the mother is provided with the medical support she needs."

Edward Maher was questioning the soldier in charge of risk assessment during the exercise in July 2013.
He said instructors did not notice for nearly an hour that his son, L/Cpl Edward Maher, was "overdue, over time, and off track" on the march.
Fellow reservists L/Cpl Craig Roberts and Cpl James Dunsby also died.
L/Cpl Maher's father questioned why a soldier, known as 1B to protect his identity, did not did not realise his son had gone "off track" until 16:10 BST when he had been expected at the next checkpoint at 15:34 BST.
Soldier 1B explained he had only noticed L/Cpl Maher's tracking device on the screen at that time.
Mr Maher said: "They were overdue, overtime, off track… do you think that your process had failed?"
"At that time sir, no I [didn't]," the soldier replied.
Earlier on Tuesday, soldier 1B told the inquest it was not in his thought process to stop the test because most soldiers were doing well during the 16-mile (26km) test on one of the hottest days of that year.
He told the hearing in Solihull that of the 78 reservists taking part that day, six had withdrawn by early afternoon - two for medical reasons.
But he said he was not concerned because the course was "tough".
"They were all completing the march on time.... at that time the two casualties had recovered within 10 minutes… none of the qualified medics there told me they needed qualified assistance," he said.
"All of the other runners were all within time… that includes Craig, that includes Ed, that includes James.
"Were there alarm bells ringing in my head at that time? No there was not."
David Turner QC, representing Cpl Dunsby's widow Bryher, asked 1B if he would have continued the march if commanding officer 1A had told him about the heat illness casualties.
"I would have looked at what was going on… everyone is pushing themselves… it takes a different type of person to operate within that theatre, at that time I would have said it would not have been within my thought process to stop that march," he said.
Soldier 1B said he told candidates to be aware of the hot weather and rising temperatures, but he did not consider heat exhaustion to be a greater risk than normal.
He also said he was not made aware of new guidance on heat injuries and when an exercise should be stopped, following the death of a marine in similar circumstances in 2008.
The inquest is continuing.
A man has described how he managed to revive a lifeless newborn baby which was found in a bus shelter.
[NEXT_CONCEPT]
The father of a reservist who died after attempting an SAS selection exercise in the Brecon Beacons has told an inquest processes "failed" that day.