John M. Patterson, a defiant segregationist who defeated and preceded George C. Wallace as the governor of Alabama as the South plunged into the violence and turmoil of the civil rights movement in the late 1950s and ’60s, died on Friday at his home in Goldville, Ala. He was 99.

His daughter, Barbara Patterson Scholl, confirmed the death, The Associated Press reported.

In a state where white supremacy, racism and brutality against African-Americans were ways of life, Mr. Patterson, supported by the Ku Klux Klan and the White Citizens’ Councils, made Mr. Wallace, who was then a state judge backed by the N.A.A.C.P., look like a milquetoast moderate when he defeated him in the 1958 Democratic primary. In those days, a primary victory was tantamount to election in heavily Democratic Alabama.

The youngest governor in Alabama history at 37, Mr. Patterson had only one term, from 1959 to 1963, and was constitutionally barred from a second consecutive term. But his tumultuous tenure coincided with centennial celebrations of the Civil War. Rebel yells and Confederate flags — one fluttering atop the State Capitol — were the backdrop for a toxic racial climate on his watch.