The underweight pup was spotted by members of the public in Stonehaven town centre late on Tuesday.
Vet Emma Thomson, of Kirkton Vets in the town, tended to the animal. She wrapped it in a blanket and took the seal pup back to the beach, where it appeared to settle.
But a few hours later, the vet received a second call to say the pup was back in the town centre.
The seal may have been looking for food after becoming separated from its mother, it is believed.
Grace Cormack, receptionist at the Kirkton Veterinary Practice, said the pup was underweight at 16kg, given his normal weight should have been around 30kg.
Ms Cormack said: “We got a call on Tuesday night and a few people had seen the pup go past. Emma caught the pup and put it on the beach, where it appeared to settle in the sand. Then we got another call in the early hours of this morning that it was back in the town centre. It had obviously been enjoying itself on the High Street.”
British Divers Marine Life Rescue were contacted and came to assist in the second rescue of the pup.
Again wrapped in a blanket, he was put in a crate – but managed to shake the door open.
Ms Cormack said: “He really wasn’t happy.”
Ms Thomson stayed with the pup through the night and the Scottish Society for the Prevention of Cruelty to Animals (SSPCA) was contacted in the morning. The animal is now at the association’s National Wildlife Rescue Centre at Fishcross, near Alloa.
“They are going to teach him to catch fish,” Ms Cormack said.
She added: “The way Emma handled the whole thing was brilliant. She caught him and stayed with him. She was brilliant.”