Walker was "a legend in his own right," said the current president of the Southern Christian Leadership Conference, which Walker also led.
Ellen Johnson Sirleaf handed over power in the West African nation's first peaceful transition in decades.
He is best known for his 1984 book The Nature of Doctrine and his engagement in the ecumenical movement.
“He was a tireless advocate of racial and gender justice in the church,” a colleague said, “often at great cost to his own career.”
Smith raised fundamental questions about the nature of religion.
The executive minister of justice and witness ministries was named 2017 Person of the Year.
“He feels he can make a difference, and I think he can,” said a fellow member of Covenant United Methodist Church.
The award honors his book The Cross and the Lynching Tree, which shows how white supremacy has affected dominant views in the church.
Samson Mulinge Mutuse and Evelyn Mueni Mulinge are among 260,000 Kenyan married couples where one spouse is HIV-positive and one HIV-negative.
Dyer was also among the first group of women ordained as Scottish Episcopal deacon and then priest.