The Grammy-winning rocker said he is proud to back someone he calls a real American success story.
The former Eagles guitarist will perform at a benefit concert for Duckworth on July 1 in Schaumburg.
The Democrat is trying to unseat Republican incumbent Joe Walsh in the new 8th Congressional District.
Congressman Walsh's office Tuesday said Duckworth can have the support of the "Hotel California liberal."
The congressman says he is more concerned with support of hard-working families.