In 1984, Levy was elected to the Suffolk County Legislature where he served for 15 years. In 2000, he was elected to the New York State Assembly, where he represented the 5th Assembly District from 2001 to 2003. Levy, then a Democrat who identified as fiscally conservative, ran for the office of Suffolk County Executive in 2003. He opposed Republican Edward Romaine. Levy entered office in 2004. On November 6, 2007, he was overwhelmingly re-elected to a second term with cross-endorsement and receiving 96% of the vote. Reflecting concerns of many residents in the county about rising numbers of immigrants, especially undocumented ones, Levy has promoted anti-immigrant policies, including employer verification of worker status and restrictions on drivers licenses for undocumented immigrants. In November 2008 seven local high school students attacked and murdered Marcelo Lucero, an Ecuadorian immigrant who had lived and worked for 16 years at a cleaners in Patchogue, Suffolk County, supporting his mother in Ecuador. Levy described the killing as not "a question of any county policy or legislation," but "a question of bad people doing horrific things." The students admitted to anti-Latino attacks, and were sentenced to varying terms.
On March 19, 2010, Levy announced that he would switch political parties, seeking the Republican Party's nomination for New York Governor, competing with former New York Congressman Rick Lazio and Buffalo developer Carl Paladino for the party nomination. Though he changed his voter registration to the Republican Party, this change came after the deadline for making such a change. For legal purposes, Levy remained a Democrat until November 2010, with the registration change taking effect after Election Day. Levy's platform focused on getting the state's financial house in order and reining in spending, while decreasing property taxes. He also called for the creation of an independent control board, much like the ones formed by the state for counties who are in financial crisis, to help address the state of New York's fiscal woes. Despite the support of state Republican chairman Edward F. Cox, Levy failed to gain the necessary support at the New York StateRepublican Convention for a "Wilson Pakula," the document necessary for non-party members to seek a party's nomination. Authorizing such a document requires a majority weighted vote of the attending members of the party; Levy received 42 percent, which barred him from entering the Republican primary, either by nomination or by petition. As a result, Levy was eliminated from the race. In 2011 Levy announced he would not seek reelection to a third term as county executive. The Suffolk District Attorney's office conducted an investigation of "issues with regard to fundraising." No charges were filed. Contributions were returned to original donors.
