Matt Horn was bitten while trying to protect his boy, who was struck first, said snake catcher Mark Pelley. Both were treated in hospital and released.
Tiger snakes, found along Australia's coast, are one of the world's most venomous reptiles.
Local newspaper the Herald Sun said the boy, Braeden, who has autism, encountered the snake in a hallway.
"He had already started playing with it when my wife saw him out of the corner of her eye," Mr Horn told the newspaper.
"It struck him on the toe and inner leg."
Paramedics called Mr Pelley to the house at midnight on Wednesday.
"The father did the right thing, he saved his son and got bitten in the process," Mr Pelley told the BBC.
"I entered the room, found the snake, safely removed it, and the father was treated by paramedics."
Mr Pelley said the snake, a protected species, will be removed from populated areas and released into the wild.
"They are the fifth or sixth most deadly land snake on the planet and they've got very powerful venom that can take effect very quickly," he said.
"You can die within half an hour of being bitten by one of these guys."
Mr Pelley said snakes were not normally aggressive, but often entered homes to escape hot weather.
"I've caught snakes in dishwashers, refrigerators, beds, cars, inside walls. You name it, I've found a snake there," he said.
Melbourne's Austin Hospital said it discharged a man and boy on Wednesday after treating them for snake bites.
An Australian man and his 11-year-old son have been bitten by a tiger snake inside their home in Melbourne.