New Jersey Gov. Chris Christie stepped in after seeing the YouTube video that the boy's parents posted had posted in 2009 - the day Christie was elected.
In the video, Jesse Koczon, 3 years old at the time, is seen sobbing after being told by a poll worker that he was too young to run for office.
"Why can't you be the governor?" the mother says.
"Because I'm too small," Koczon says through his tears.
Christie responded on Twitter: "Don't worry Jesse, people gave plenty of reasons why I couldn't be Governor, though being too small wasn't one of them."
On Wednesday, Christie proclaimed the boy honorary governor for the day, and the pair got straight to work.
The boy said in a news conference that he can't raise property taxes or else the people won't want him to be governor anymore.
His fraternal twin brother, Brandon, was named honorary lieutenant governor for the day.
The Associated Press has contributed to this report.