Joni Kay Ernst is an American politician and retired military officer serving since 2015 as the junior United States senator from Iowa. She is a member of the Republican Party.
After graduating from Iowa State University, Ernst joined the United States Army Reserve. She served in the Iowa Army National Guard from 1993 to 2015, retiring as a lieutenant colonel. During the Iraq War, she served as commanding officer of the 1168th Transportation Company in Kuwait and later commanded the 185th Combat Sustainment Support Battalion at Camp Dodge.
Ernst served in the Iowa State Senate from 2011 to 2014 and as auditor of Montgomery County from January 2005 to January 5, 2011. She was elected to the U.S. Senate in 2014 and reelected in 2020. As chair of the Senate Republican Policy Committee from 2023 to 2025, Ernst was the fourth-ranking Republican in the Senate. During her Senate tenure, she has called for reforms to Medicare, Medicaid, and Social Security. During the Trump administration, she expressed concern about Trump's trade war with China, and as a war hawk, criticized some of his foreign policy. While supporting both of Trump's nominees for EPA administrator, she expressed concern over their commitment to the Renewable Fuel Standard.
On September 2, 2025, Ernst announced that she would not seek reelection in 2026.
