Kristi Lynn Arnold Noem is an American politician serving since 2025 as the 8th United States secretary of homeland security. A member of the Republican Party, she served from 2019 to 2025 as the 33rd governor of South Dakota and from 2011 to 2019 represented South Dakota's at-large congressional district in the U.S. House.

Noem was born Kristi Lynn Arnold to Ron and Corinne Arnold on November 30, 1971, in Watertown, South Dakota, and raised with her siblings on the family ranch and farm in rural Hamlin County. She has Norwegian ancestry. In 1990, Noem graduated from Hamlin High School and was crowned South Dakota Snow Queen. Her father was killed in a farm machinery accident in 1994.

She married Bryon Noem in 1992, in Watertown, South Dakota. They have three children. In 2011, when Noem moved to Washington to take her congressional office, her family continued to live on a ranch near Castlewood, South Dakota.

Noem is a Protestant. As of 2018, her family attended a Foursquare Church in Watertown, South Dakota. She is a grandmother.