 In November 1868, during his fourth term as D.A., Hall was elected Mayor of New York City as a Democrat supported by Tammany Hall.He was re-elected mayor in 1870, again on the Tammany ticket, serving two terms from January 1, 1869, to December 31, 1872.As mayor, Hall was unpopular for a myriad of reasons, partly due to the ongoing political clashes between Anglo "Nativists" and the Irish population.