Born in Bloomington, Indiana, the only child of Josephine (née Bracken) and William Lincoln McMillen.

Her father was an English professor and her mother studied music but gave up her career once her daughter was born.

[2][3] In 1917, she enrolled to study chemistry at Indiana University, graduating with Phi Beta Kappa, Sigma Xi, and other honors.

Clara Kinsey died on April 30, 1982, and is buried with her husband in Bloomington, Indiana.

Laura Linney was nominated for the Academy Award for Best Supporting Actress for her portrayal of Clara McMillen in the 2004 film Kinsey.