 During his term as mayor Sullivan worked to develop the new Worcester Airport, blacktop the city's streets, covering up the old streetcar tracks that were no longer in use and to clean up the city's pension system.Sullivan was reelected mayor in 1948 and he served until 1949 when Worcester changed its city government to a Plan E format, under which the mayor is no longer popularly elected but is instead selected by votes of the City Council.On November 3, 1948 Sullivan was elected as Lieutenant Governor of Massachusetts, he was also reelected as mayor of Worcester and until 1949 he served in both capacities.