Don Harmon is an American attorney serving as a Democratic member of the Illinois Senate, representing the 39th District since 2003. His district includes Chicago's Austin neighborhood and the suburbs of Oak Park, Addison, Bensenville, Elmwood Park, Franklin Park, Melrose Park, Northlake, River Grove, Rosemont, Schiller Park, and Stone Park.

The Illinois Senate is the upper chamber of the Illinois General Assembly, the legislative branch of the government of the State of Illinois in the United States. The body was created by the first state constitution adopted in 1818. Under the Illinois Constitution of 1970, the Illinois Senate is made up of 59 senators elected from individual legislative districts determined by population and redistricted every 10 years; based on the 2020 U.S. census each senator represents approximately 213,347 people. Senators are divided into three groups, each group having a two-year term at a different part of the decade between censuses, with the rest of the decade being taken up by two four-year terms. This ensures that the Senate reflects changes made when the General Assembly redistricts itself after each census.