Thurman was first elected to public office in 1974, when she won a seat on the city council of Dunnellon, Florida, on which she served until 1983. She served as Mayor of Dunnellon from 1979 to 1981. She served in the Florida State Senate from 1983 to 1993.
Congresswoman
Florida gained three congressional districts after the 1990 census. One of them was the 5th District, which stretched from Gainesville to the far northern portion of the Tampa Bay Area. It was an open secret that this district was drawn for Thurman. She was elected to the House from that district in 1992 and was reelected four more times with no serious opposition. Thurman was recognized as an expert on health, veterans, and tax issues. She was only the sixth woman to serve on the House Ways and Means Committee. On Ways and Means she fought for lower prescription drugs, increased access to health insurance, and tax relief. Prior to her appointment to Ways and Means in 1996, Congresswoman Thurman served on both the House Agriculture Committee and the Committee on Government Reform and Oversight. After the 2000 census, the Republican-controlled Florida legislature reconfigured the 5th to make it friendlier to Republicans. She lost heavily Democratic Gainesville and surrounding Alachua County while picking up some heavily Republican territory between Tampa and Orlando. The new 5th contained much of the territory located in the State Senate district of that body's President Pro Tem, Ginny Brown-Waite. Nonetheless, Thurman ran for reelection. Even though the redrawn district had gone narrowly for George W. Bush in 2000, Thurman just barely lost to Brown-Waite. Since Thurman left office, the Democrats have cleared the 40 percent barrier in the district, now numbered as the 11th, only once.
Post-Congress career
In 2005 Thurman was elected Chairman of the Florida Democratic Party, succeeding Chairman Scott Maddox, who resigned in order to seek the Democratic nomination for governor. Thurman resigned on November 12, 2010 following the midterm elections. Thurman is a member of the ReFormers Caucus of Issue One.
Personal
Her son Macky Thurman unsuccessfully ran for the state house in 2006. Her husband was a circuit judge.