Culkin's real middle name is Carson, after Kit Carson, an American frontiersman from what was known as the Old West.
The five finalists for Culkin's middle name were Macaulay Culkin, Shark Week, Kieran, TheMcRibIsBack and finally Publicity Stunt.
The poll was open until Christmas Eve with Culkin encouraging his fans to vote.
"Sure, I might have gold-plated watercraft, and chrome-plated invisibility cloaks, but all I want for Christmas is a new middle name," Culkin said.
"And then you can be all 'Oh, you got your wife a beautiful portrait of your family? Well, I chose Macaulay Culkin's middle name.' And they will cry and cry. Don't be the kind of person who cries on Christmas. Be the kind of person that chooses my new middle name."
After more than 100,000 votes, the overwhelming winner ended up being Macaulay Culkin with close to 61,000 votes.
It means the former child actor's name will be changed to Macaulay Macaulay Culkin Culkin.
The 38-year-old actor previously suggested the laughable possibility of his middle name becoming Macaulay Culkin telling late night host Jimmy Fallon it would give him an opportunity to troll fans.
"So, if somebody comes up to me at the airport, and says, 'Excuse me, are you Macaulay Culkin?' I'd go, 'Well Macaulay Culkin is my middle name," Culkin said.
Culkin announced the winner on Christmas Day, saying the double name had "a nice ring to it".
