Christie says Tony Mack should step down because his indictment on corruption charges hinders his ability to serve.
A grand jury handed up an indictment last week accusing the mayor, his brother and an associate of taking part in a scheme to influence the development of a garage on city-owned land in exchange for $119,000 in bribes.
The governor, a former federal prosecutor, says the resignation of any public official who has been indicted is in the best interest of the people they serve.
Mack has continued in his position despite a no-confidence vote by the Trenton City Council.
Hamilton Mayor John Bencivengo resigned last month after being convicted of taking bribes.