In 1924 newly elected Mayor of Philadelphia W. Freeland Kendrick asked President Calvin Coolidge to lend the City a military general to help him rid Philadelphia's municipal government of crime and corruption. At the urging of Butler's father, Coolidge authorized Butler to take the necessary leave from the Corps to serve as Philadelphia's director of public safety in charge of running the city's police and fire departments from January 1924 until December 1925. He began his new job by assembling all 4,000 of the city police into the Metropolitan Opera House in shifts to introduce himself and inform them that things would change while he was in charge. Since he had not been given authority to fire corrupt police officers, he switched entire units from one part of the city to another, to undermine local protection rackets and profiteering.