CHICAGO (CBS) — Civil rights activist Willie Barrow, who was President Barack Obama’s godmother, has died at the age of 90.

Rev. Jesse Jackson confirmed Barrow died overnight. Jackson called Barrow a “global citizen” who he’ll miss very much.

The diminutive Barrow was known as the “Little Warrior” for her fight for civil rights. She had been hospitalized for more than a week with a blood clot in her lung.

Rev. Michael Pfleger called Barrow a force of nature.

“She was just so spontaneous, never holding back what she thought or what she believed; about life, about marriage, about raising children – you know, she had lost a son earlier in her life – but about what people ought to be fighting for,” he said.

Pfleger, a fellow activist, said Barrow was short in stature at 4’11”, but she was a giant in the fight for civil rights.

“When you would get discouraged, or get disgusted to see how … slow change was taking, Reverend Barrow was one of those who had been there since the beginning of the civil rights movement. She’d always say to me, ‘Stay on the battlefield. Keep doing what you’re doing. Keep fighting,’” he said.

Born Willie Taplin in rural Texas in December 1924, she one of seven children raised by a Baptist minister and his wife.

Barrow had an impact on the civil rights movement when she was only 11. In 1936, she refused to get off a school bus reserved for whites only.

In an interview when she was honored by the Chicago Urban League three years ago, she spoke of her outrage as a child, when black students had to walk to school, while white children rode the bus.

“I told the driver, I said ‘We all are alike, we all got butts, and all we got to do is sit down on the seat, and you’ve got plenty of room. So why you want me to get off this? Because I’m black? No, we’ve got to change that,” she said.

She felt the call to ministry when she was only 16. She attended Warner-Pacific Theological Seminary in Portland, Oregon, and was ordained as a minister. During her studies, she built a church in Oregon.

After marrying her husband, Clyde Barrow, in 1945, they followed the migration from the South to Chicago. She studied at the Moody Bible Institute, and in the 1950s became active in the civil rights movement, joining Rev. Martin Luther King Jr. on the front lines of the struggle.

Barrow was one of the founders of the Chicago chapter of Operation Breadbasket in 1962. That organization later became Operation PUSH. She replaced Jackson as executive director of Operation PUSH in 1984, until she retired in 1995. It later merged with the National Rainbow Coalition, forming the Rainbow/PUSH Coalition in 1996.

Barrow also was a field organizer for the march on Washington in 1963 and the march on Selma, Alabama, in 1965.

In the late 1950s or 1960s, she became an associate pastor at Vernon Park Church of God in Chicago, and was a co-pastor at the church at the time of her death.