A Republican, Kate Murray became the first woman and first Levittowner elected to the New York State Assembly from the 19th Assembly District on February 3, 1998. She represented the district until 2001. Murray then served as Clerk for the Town of Hempstead. She was appointed Supervisor by the Hempstead Town Board in 2003, after being tapped by Nassau County Republican Chairman Joseph Mondello when Supervisor Richard V. Guardino Jr. resigned. She won election to the position of Supervisor in the fall of 2003 and was re-elected in 2005 with over 60% of the vote. She is a close ally of Mondello, who also held the post of Republican Party State Chairman during the 2000s. Although the county GOP organization's strength has declined precipitously from what it had been in past decades—as demonstrated by its loss of control in the neighboring Town of North Hempstead, under Democratic administration from 1989 onward, as well as the county government itself between 2002 and 2009—the Town of Hempstead remains a GOP stronghold. Her governance was marked by a three-step downgrade of Hempstead's credit rating in Murray's final year as supervisor by Standard & Poor's, which cited the drawing down of reserves and the settlement in a complex tuition payment for the Fashion Institute of Technology. That followed a downgrade a year earlier by S&P, which means Murray's governance led to four downgrades in her final two years on the job. In May 2015, Murray announced her candidacy for Nassau County District Attorney. She lost to Madeline Singas. Kate Murray is credited with losing the election due to the failure of The Lighthouse Project, which she opposed and downsized, and which would have created a large new development at the site of the Nassau Coliseum that also would have served as a newly renovated home for the New York Islanders. She was frequently referred to as "Hate Murray" on various Islanders fan pages and message boards. After leaving her town office and following her defeat for the DA's position, she took a job with Nassau County Community College. In early 2019, Murray announced that she was going to attempt a return to public office by running for Town Clerk. She previously held the office. She also apparently believes that Islander fans have gotten past her role in the collapse of the Lighthouse project and will not cast their votes on that basis.
