Lewis had been supporting Sen. Hillary Clinton, D-N.Y., but said overwhelming support for the Illinois senator in his Georgia district was one reason for his change of heart, The Atlanta Journal-Constitution reported.
"Something's happening in America, something some of us did not see coming," Lewis said in a statement. "Barack Obama has tapped into something that is extraordinary."
Lewis's support for his friend Clinton over Obama had sparked outrage from Georgia's African-American community.
Disney's 'Jessie' to feature network's first engagement
Iranian woman stops the execution of son's killer