Walker was born in Putnam County, Georgia, the youngest of eight children, to Willie Lee Walker and Minnie Lou Tallulah Grant. Her father, who was, in her words, "wonderful at math but a terrible farmer," earned only $300 ($4,000 in 2013 dollars) a year from sharecropping and dairy farming. Her mother supplemented the family income by working as a maid. She worked 11 hours a day for $17 per week to help pay for Alice to attend college.
Living under Jim Crow laws, Walker's parents resisted landlords who expected the children of black sharecroppers to work the fields at a young age. A white plantation owner said to her that black people had "no need for education". Minnie Lou Walker, according to her daughter, replied "You might have some black children somewhere, but they don't live in this house. Don't you ever come around here again talking about how my children don't need to learn how to read and write." Her mother enrolled Alice in first grade when the girl was four years old.
Growing up with an oral tradition, listening to stories from her grandfather (who was the model for the character of Mr. in The Color Purple), Walker began writing, very privately, when she was eight years old. "With my family, I had to hide things," she said. "And I had to keep a lot in my mind."
In 1952, Walker was accidentally wounded in the right eye by a shot from a BB gun fired by one of her brothers. In 2013, on BBC Radio's Desert Island Discs, she said the act was actually deliberate but she agreed to protect her brother against their parents' anger if they knew the truth. Because the family had no car, the Walkers could not take their daughter to a hospital for immediate treatment. By the time they reached a doctor a week later, she had become permanently blind in that eye. When a layer of scar tissue formed over her wounded eye, Alice became self-conscious and painfully shy. Stared at and sometimes taunted, she felt like an outcast and turned for solace to reading and to writing poetry. When she was 14, the scar tissue was removed. She later became valedictorian and was voted most-popular girl, as well as queen of her senior class, but she realized that her traumatic injury had some value: it had allowed her to begin "really to see people and things, really to notice relationships and to learn to be patient enough to care about how they turned out". After high school, Walker went to Spelman College in Atlanta on a full scholarship in 1961 and later transferred to Sarah Lawrence College, graduating in 1965. Walker became interested in the U.S. civil rights movement in part due to the influence of activist Howard Zinn, who was one of her professors at Spelman College. Continuing the activism that she participated in during her college years, Walker returned to the South where she became involved with voter registration drives, campaigns for welfare rights, and children's programs in Mississippi.
On March 17, 1967, she married Melvyn Roseman Leventhal. She worked as writer in residence at Jackson State College (1968–69) and Tougaloo College (1970–71) and was a consultant in black history to the Friends of the Children of Mississippi Head Start program.