Lewis, 53, succeeds Jonathan Linen, vice chairman of American Express Co.
The National Urban League, a nonprofit organization with 114 affiliates in 34 states, works to help blacks achieve economic, racial and academic equality.
Lewis says the organization will continue to focus on economic equality for blacks, with an emphasis on low-income and working people struggling to benefit from the strong economy.
“Although unemployment for the African-American community is down, it remains much higher than that of the majority,” Lewis said. “And we also know the rate of investing for African Americans is low compared to that of the average American. The economic iron is hot and now is the time to strike.”