"I am proud to be here to endorse Donald Trump," said Mr. Christie, adding that the two have known each other for ten years, and that Trump "will do exactly what needs to be done to make America a leader around the world again."
"The best person to beat Hillary Clinton on that stage last night is undoubtedly Donald Trump," Christie said, referring to Thursday's GOP presidential debate.
Christie also added he would appear at Trump's rally in Oklahoma on Friday evening. Oklahoma is one of the more than dozen states holding primaries on March 1, Super Tuesday.
The move comes as Sen. Marco Rubio, R-Fla., intensifies attacks against Trump. Christie and Rubio sparred several times on the debate stage before Christie dropped out earlier this month, although Rubio's campaign has tried to meet with Christie since then.
The New York Times reported Christie had been angry with Rubio since dropping out of the race.