Jean Graetz, who was among the few white people in Montgomery, Ala., to participate in the city’s civil rights movement in the 1950s — pushing forward even as she faced slashed tires, obscene phone calls and multiple bombings — died on Wednesday at her home in Montgomery. She was 90.

The cause was lung cancer, said Kenneth Mullinax, a family friend. She died just three months after her husband, Robert, with whom she had partnered in her civil rights efforts.

“Bob and Jeannie were just one of those couples, like Romeo and Juliet,” Mr. Mullinax said. “One could not survive without the other.”

The couple arrived in Montgomery in 1955 after Mr. Graetz, a newly minted Lutheran minister trained in Ohio, was assigned to a predominantly Black church. Black Lutherans were rare in Alabama, and it was even more rare for a white minister to preach to them, let alone to live in their neighborhood as the Graetzes did.

Although Mr. Graetz was the headliner of the couple, preaching to his flock every Sunday, Mrs. Graetz played an equal part behind the scenes, organizing events and building connections with members of the city’s civil rights movement.

“My mother didn’t like to look at them as a team,” her daughter Carolyn Graetz Glass said in a phone interview. “She was happy to let our dad shine. But there was no Bob without Jeannie, and no Jeannie without Bob.”

Rosa Parks, one of their neighbors, used a room in the church, Trinity Lutheran, to hold meetings of the local N.A.A.C.P. chapter. When Mrs. Parks was arrested in 1955 for refusing to give up her seat on a segregated bus, Mrs. Graetz was among the women who began planning what turned into a yearlong boycott of the city’s public transportation. The boycott would propel the Rev. Dr. Martin Luther King Jr., who emerged as its leader, into the international spotlight.