Steve Whitehouse, 49, spotted the fire, caused by an e-bike battery explosion, during his morning collection round with driver Kevin Marriott.
The dad of one climbed a wall three times to reach a balcony.
From there, he got a woman, a man and their dog to safety from a first-floor flat in Tipton, West Mids.
The man, in his 20s, was treated in hospital for the effects of smoke.
Fire chief Chris Green said: “It was clear as we approached that this was a severe fire.
“I have no doubt that, without Steve’s incredible bravery, the outcome could have been very different.
“I have no idea how he managed to do what he did. It was heroic.
“The fire and smoke were coming out of the property’s rear door like a blow torch.
“One rescue would have been remarkable.
“To save the lives of two people and a dog is staggering.
“We will be putting him forward for official recognition.”