"With that great voice of his, he just rumbled that out, and then went on and used that as a theme," Buffett commented in "The Snowball."
After King's speech at Grinnell, Buffett felt "a sense of urgency to do something more for civil rights too," Schroeder wrote.
"My politics became more overt after my dad died," Buffett said in "Becoming Warren Buffet." "You know, in 1776, Thomas Jefferson wrote 'All men are created equal' and then when they wrote the Constitution, they all of a sudden decided: No, it was just three-fifths of a person if you were black. I mean that struck me as kind of crazy."
Buffett worked with his friend Rosenfield to grow the college's endowment and help students with financial need. He also served on the Grinnell College Board of Trustees for years after, a spokesperson for Grinnell College tells CNBC Make It.
The speech inspired Buffett to fight the anti-Semitism of older members of his family and his community.
For example, Jews couldn't join local country clubs for years, the Omaha World-Herald reported, until Buffett joined the all-Jewish Highland Country Club. This pressured Omaha Club to accept his Jewish friend as a member.
Buffett and Susie were among the first non-Jews to join an all-Jewish country club in Omaha and thus encouraged other clubs there to permit Jewish members, The New York Times later reported.
"Civil rights changed my views," Buffett said in "Becoming Warren Buffett."
King would have turned 89 years old this year, just a year and a half older than Buffett.
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