United States Senator, First Lady of Missouri. She was born and raised in Washington, D.C., the daughter of Reginald Carpenter, a plumber, and Alvina Carpenter (née Sullivan), a hairdresser. She attended Anacostia High School, where she met her future husband, Melvin "Mel" Carnahan, the son of a Congressman from Missouri. She attended George Washington University, where she was a member of the Kappa Delta sorority. She graduated in 1955 with a degree in Business and Public Administration, the first person in her family to graduate from high school and college. She married Mel on June 12, 1954, at Memorial Baptist Church in D.C. They settled in Missouri, where Mel practiced law. The couple had four children.

A Democrat, Mel was elected Governor of Missouri in 1992, serving from 1993 to 2000. Jean was actively involved in all of his campaigns and helped write his speeches. As the state's first lady, she advocated for daycare accessibility for working families, support for survivors of domestic abuse, childhood immunization, the arts, Habitat for Humanity, and more. She also renovated the Governor's Mansion to make it more accessible to the public and authored two books about Missouri history.

In 2000, Mel ran for a seat in the US Senate but was killed in an airplane crash three weeks before the election. Missouri election law would not allow his name to be removed from the ballot so close to the election. Acting Governor Roger B. Wilson determined that he would appoint Jean to fill her husband's seat if he were to win the election posthumously. She accepted the tentative nomination, and the Carnahans won the election. Mel was the first U.S. Senator elected posthumously. Jean was to fill his vacant seat until a special election the following year. This made her the first woman to represent Missouri in the U.S. Senate. She campaigned to fill the rest of her husband's six-year term but was narrowly defeated. She served in the Senate for nearly two years, focusing on national security, healthcare for the military, and curbing insider trading. She was part of the first Congressional delegation to Afghanistan after the Sept. 11, 2001, terrorist attacks.

After leaving Congress, she continued her life as an activist and author, writing six more books. She remained active in the Democratic Party, particularly supporting women running for office, as well as some of her own children who entered politics.