Sengstacke was also a civil rights activist and worked for a strong black press, founding the National Newspaper Publishers Association in 1940, to unify and strengthen African-American owned papers.

It rapidly achieved high circulation in the early 20th century as the African-American population expanded in Chicago and other northern cities by the Great Migration.

[3] Abbott groomed Sengstacke to take over the Chicago Defender, paying for his nephew's education at Hampton Institute, his own alma mater and a historically black college.

His role was challenged by Edna Abbott, his uncle's widow, and he had to continue a suit for 10 years before gaining control of the newspaper company.

[2] During the years of World War II, Sengstacke acted as a national spokesmen for African-American journalism and publishers.

He worked with President Franklin D. Roosevelt to ensure that African-American reporters were admitted to presidential press conferences.

In 1947, Sengstacke helped co-found Americans for Democratic Action with: Joseph Alsop,[4] Stewart Alsop,[4] Chester Bowles,[5] John Kenneth Galbraith,[4][6] Leon Henderson,[5] Hubert Humphrey[4][5] James I. Loeb, Reinhold Niebuhr,[4][6] Joseph P. Lash, Joseph L. Rauh, Jr.,[4] Walter Reuther,[6] Eleanor Roosevelt,[4][5][6] Arthur Schlesinger, Jr.,[4] and Wilson W. Wyatt[4] One of Sengstacke's major goals at the national level was to desegregate the armed forces, particularly given the sacrifices of African Americans in the Armed Forces during World War II.

The second wave of migration was chiefly to California and other West Coast cities, as people were attracted by jobs in the defense industry.

In the postwar period, veterans and other African Americans pressed for civil rights in the South, where most black citizens had been disenfranchised since the turn of the century, kept in second-class status under Jim Crow, confined to segregated spaces.

In 1956, Sengstacke turned the weekly Chicago Defender into a daily, to keep up with changing conditions and report on black progress.

In the late 1960s Sengstacke purchased the financially ailing black newspaper, the Pittsburgh Courier, which had achieved a national reputation during the 1930s and 1940s.

When asked about his decision, Sengstacke replied: I have supreme confidence in Hazel, and believe that she will continue to do a great job as editor-in-chief as she did as city editor.

In 2002, he said his plans for the New Pittsburgh Courier included more emphasis on in-depth features and arts, creating a web presence — which neither it nor the Defender had at the time — and changing its political outlook from liberal to "conservative independence".