Joseph Esposito, called by a Wall Street Journal source “the four-star general of the largest police force in the country,” retired yesterday as “chief of department” for the New York City police after 44 years on the force. The Journal says he has spent 12 years “as the longest-serving chief in department history, with a reputation as a steady strategist, a cop’s cop and a loyal defender of the agency with enough charisma to doff his hat at protesters during an Occupy Wall Street demonstration in Times Square.” The department could have a different leader if a newly elected mayor replaces Commissioner Raymond Kelly. “He’s not a household name,” said civil liberties lawyer Norman Siegel. “Kelly and [Mayor Michael] Bloomberg get the credit, but you have to recognize the operational person. That was Chief Esposito.” Esposito left because the reaches the mandatory retirement age of 63 tomorrow. Among many rank-and-file officers in the 35,000-member force, Esposito has achieved a near-mythical status.