"Carer Jenny Shaw said she suffered burns on her paws and was in a lot of pain, but was on the road to recovery.
She was put on an IV drip and is on antibiotics and pain relief treatment.
"She is lovely - very docile - and she has already got an admirer. A male koala keeps putting his arms around her," Ms Shaw said. "She will need regular attention and it will be a long road to recovery, but she should be able to be released back into the wild in about five months."
"Mr Tree said he was surprised by the reaction to the photograph, which was snapped by Mark Pardew - a fellow CFA volunteer - on a mobile phone.
Mr Tree said he was in the middle of backburning at Mirboo North when he saw the stricken koala.
"I could see she had sore feet and was in trouble, so I pulled over the fire truck. She just plonked herself down, as if to say 'I'm beat'," he said.
"I offered her a drink and she drank three bottles.
"The most amazing part was when she grabbed my hand. I will never forget that."
Mr Tree and his brigade then received an emergency call-out to save a house, but minutes later Sam was picked up by wildlife carers.
She is one of 22 koalas, 14 ringtail possums, several wallabies and eastern grey kangaroos that have been handed into Gippsland carers.