Christie, a longtime Trump ally, was speaking the day after reports broke that Trump had asked Comey to drop an FBI investigation looking into his former national security adviser Michael Flynn's ties to Russia. The controversy has raised questions about whether Trump obstructed justice.
Speaking at a NJ Transit facility, Christie at first told reporters he would not comment on events in Washington that he's "not involved in."
Following some prodding, however, Christie defended Trump's actions to fire Comey.
"I think the President has been underserved by his staff. I think I've said that two or three times, but the fact is that what I do know as someone who has run two pretty large operations is that those decisions need to be made by the executive," Christie said. "Only the person who is being served day-to-day knows for sure how well they are served and knows any perception of success or lack of success."
Christie, a former federal prosecutor, denied speculation that he may be vying for the now-open FBI director role with an emphatic "no," adding that he'll be finishing out his term, which ends next January.
He seemed to offer some veiled advice to the administration in an apparent reference to the deluge of leaks plaguing the White House.
"For most of the time, there are very, very few leaks out of this (Christie's) administration. I think the reason for that is that we are all rowing in the same direction, and people know that we support each other," Christie said. "When you have a system where people are supporting each other and people are working well with each other, you don't have the need to put forward a specific agenda."
Speaking specifically about the White House, Christie added, "Rather than worry about how to plug leaks, it's about how to stop them from the beginning -- setting a certain spirit."
The New Jersey governor also had some words for members of Congress who plan to bring impeachment
charges against the President in the wake of the Comey memo revelation.
"I'm the only person in this room who has prosecuted obstruction of justice cases and won. They are very difficult to prove," Christie said.