Williams, who had served on the Phoenix city council since 1989, was selected by the council to serve as an interim mayor of the city on March 29, 1994, following the resignation of former mayor Paul Johnson (politician). Johnson, who was announcing his candidacy for the office of governor, was forced to resign his position due to state requirements forbidding current officeholders from seeking another office. Coincidentally, Johnson had first been elevated to the office of mayor under similar circumstances when former mayor Terry Goddard had resigned his office to run for governor in 1990.
Williams chose not to seek election to the office of mayor during the 1994 special election, and resumed her duties as councilwoman on November 3, 1994. Williams chose to challenge the new incumbent Skip Rimsza for the office during the regular elections in 1995 but was defeated; having not run for reelection in her council seat, she left the city council in 1996. Williams chose to run for a new term in 2007 and was elected to a new four-year term on the Phoenix city council on September 11, 2007.