Moses is the latest African American leader of that era to die in the past year, including John Lewis, Vernon Jordan, C.T. Vivian, Charles Evers, and Gloria Richardson.
"He was a strategist at the core of the voting rights movement and beyond. He was a giant," Derrick Johnson, president of the National Association for the Advancement of Colored People, wrote on Twitter.
Raised in New York's Harlem neighborhood, Moses was teaching high school math in the city when in 1960 he traveled to Mississippi to search for people to attend a conference of the Student Nonviolent Coordinating Committee (SNCC), according to the SNCC Digital Gateway, a website affiliated with Duke University that records the organization's history.
Moses helped put the promotion of voter registration on the SNCC agenda and went on to participate in many of the frontline struggles in the South that were often met with violent resistance.
His travels to the South awakened Moses to the violation of African Americans' civil rights when Black people still lacked equal rights under the law.
"I was taught about the denial of the right to vote behind the Iron Curtain in Europe; I never knew that there was denial of the right to vote behind a Cotton Curtain here in the United States," Moses said.
His low-key style contrasted with the soaring charisma of leaders like the Reverend Martin Luther King Jr., as Moses "avoided publicity and was reluctant to assert himself as a leader," according to Stanford University's Martin Luther King Jr. Research and Education Institute.
But King himself praised Moses' grassroots, community-based leadership as an "inspiration," the King institute said.
Moses moved to Canada to avoid the military draft during the Vietnam War in 1967 and later lived in Tanzania for several years, the institute said.
He returned to the United States to complete a doctorate at Harvard University, where he won a MacArthur Foundation "Genius" grant, which he used to promote the Algebra Project to improve math skills for poor children.
Moses remained president of the Algebra Project until his death.
He died at home in Hollywood, Florida, the New York Times reported, citing his daughter Maisha Moses. Reporting by Daniel Trotta; editing by Jonathan Oatis