A koala owes its life to a fire captain and his rescue team for some quick-thinking marsupial mouth-to-mouth that brought it back from the brink.

The koala was first believed to have been hit by a car, then it fell out of a tree and was caught before needing mouth-to-mouth and CPR.

The lucky koala has been dubbed Sean after Langwarrin Country Fire Authority (CFA) Captain Sean Curtin, who led the rescue effort in the outer Melbourne suburb on Thursday night.

Sean was first spotted on the side of a road, believed to have been hit by a car.

But when Wildlife Victoria officers arrived it scrambled up a tree, and the CFA was brought in so a truck with an extended ladder could reach it.

Sean lost consciousness and fell into a blanket held by firefighters, a move Mr Curtin says saved its life.

A wildlife officer then leapt into action with the kiss of life.

Mr Curtin said the crew had thought the koala was dead in the tree.

"It appeared that it was passed away in the tree while members of the crew were rescuing it," he told AAP.

Sean the koala was brought back to life by fire crews after they performed mouth-to-mouth resuscitation. (Langwarrin and Frankston CFA) ((Langwarrin and Frankston CFA))

"Then Wildlife Victoria performed mouth-to-mouth and compressions and we gave it some oxygen therapy and it regained consciousness."

Mr Curtin told 9NEWS that the CFA had a strong connection with koalas, particularly since several of the animals were nursed back to health by firefighters during the Black Saturday bushfires.

"To be able to put it back in the community and have a fantastic result like that from a koala is absolutely brilliant," Mr Curtin said.

Kylie Juraschek, also with the CFA, said the crew were relieved that Sean was recovering after the ordeal and said the team had put a lot of work into his rescue.

"It is very rewarding because unfortunately we get called out to a lot of sad situations," she said.

"It was just a very, very good feeling and pleasing to see."

Sean is resting up in a wildlife hospital and appears relatively unscathed.

"It's doing OK but it needs to assessed by a vet today. It doesn't have any visible injuries and seems to be in good shape," a Wildlife Victoria spokeswoman said.

Today, the koala is recovering in wildlife officer Michelle Thomas' care.

“First time I've done CPR on a koala so interesting day,” she said.

Sean was initially mistaken for another local koala, "Sir Chompsalot", before being given its own moniker.