New Jersey Attorney General Jeffrey Chiesa has been tapped to temporarily fill the Senate seat left vacant by the late Sen. Frank Lautenberg, who died on Monday.
Chiesa, a Republican, will hold the seat until a special election to be held on October 16.
"I said on Monday I was going to select the person I thought was going to be the best person to represent New Jersey between now and Oct. 13," Christie told reporters.
"During the last few days as I’ve gotten to deliberate on this decision, it became clear to me that Attorney General Chiesa would be the best person to represent the people of New Jersey in the United States Senate."
"I'm perfectly comfortable with that decision," the governor added.
Chiesa served as chief counsel to Christie from January 2010 through December 2011, when he was nominated to be New Jersey attorney general.
The two previously worked together both at the United States attorney's office and during Christie's transition into the governor's office.
"The governor has given me some extraordinary chance to serve public life, none of which I expected," Chiesa said.
"I look forward to doing my best in this job over the next few months."
On Tuesday, Christie announced that he would call a special election instead of appointing an interim senator to fill the seat until the originally scheduled election in November 2014.
More from GlobalPost: Christie calls special October election to replace Sen. Lautenberg
Christie came under fire from some national Republicans who wanted Christie to appoint a fellow GOP to hold the seat for the next 18 months, giving Republicans in Congress and extra vote.
Both winners and losers in the October special election will have the chance to compete in the Nov. 2014 election for the full six-year term.
Democratic Rep. Rush Holt has already announced that he plans to run in the special election.
He will likely face Newark Mayor Cory Booker, who was already planning his candidacy for Nov. 2014.
Former Bogota, NJ., Mayor Steve Lonegan, is the first Republican to announce he's seeking the Senate seat.