Daddy, let's get a sandwich and a Coke." It was this urging by Hosea Williams's young sons, ages 6 and 8, in a Savannah, Ga., drugstore in the '50s that became the clarion cry leading him to the front lines of the civil rights movement.

"I started cryin'," Williams, who died on Nov. 16 of cancer at 74, told author Howell Raines years later. "The truth was they were black, and [white people] didn't 'low black people to use them lunch counters."

First with the NAACP, and then as one of Martin Luther King Jr.'s right-hand men—King's widow Coretta hails him as "our beloved field general"—Williams hurled himself enthusiastically into the battle. "He had a passion and compulsion about justice," says former U.N. Ambassador Andrew Young, another King lieutenant. "It was his determination to not be subjugated or intimidated that made him so fiery."

The son of parents who never married (and who were both blind), Williams escaped the poverty of rural Attapuigus, Ga., by enlisting in the Army at 16. After receiving a Purple Heart in World War II—he suffered severe injuries when a German bomb went off in his foxhole—he returned to Georgia to finish high school at 23, then went on to earn a master's degree before landing a job as a chemist for the U.S. Department of Agriculture.

After King's 1968 assassination, Williams continued his activism, leading a march into virtually all-white Forsyth County, Ga., in 1987. But he became best known in Atlanta for his work with the poor, hosting huge holiday dinners that fed as many as 40,000 people annually. This year's Thanksgiving celebration, paid for by rap impresario Sean "Puffy" Combs, was only the second one that Williams has missed in 30 years.