Smith was first elected to the New York State Senate in a 2000 special election. He was elected minority leader in January 2007, succeeding David Paterson. After the 2008 state elections, Democrats gained a majority of seats in the State Senate for the first time in 40 years, and Smith was subsequently chosen as Majority Leader and Temporary President of the body in January 2009. He was the first African American to hold this position. However, on June 8 of that year, Sens. Pedro Espada Jr. and Hiram Monserrate joined with the thirty Republicans in voting to replace Smith as Senate Majority Leader, triggering the 2009 New York State Senate leadership crisis. The crisis concluded the following month when Espada and Monserrate abandoned their alliance with the Republicans and rejoined the Senate Democratic Conference. As a compromise, Smith retained only the title of Temporary President of the Senate, with the title of Majority Leader going to Espada.