In the late 1860s Overall moved to Omaha, where he continued his civil rights activism and civic involvement. When he arrived, Omaha schools were segregated and education for blacks was very poor. In 1868, he led in a fight to end the segregation and in 1869 the system ended. Overall briefly resigned from the post in 1879 to focus on his business activities, but soon was reinstated and continued to work for the postal service until two weeks before his death. In 1871, he organized the first literary society in Omaha, then known as the Progressive Age Association. W. H. Washington, Rev. R. Ricketts, E. S. Clellans, J. Johnson, C. C. Cary, and Overall's wife. In Omaha, he worked closely with
Cyrus D. Bell, Dr. Stephenson,
John Lewis, and Samuel Colman in organizing the city's blacks; working to support black newspapers and local and national improvement in black rights. He was selected at the first State Convention of blacks ever held in Nebraska to be a delegate to the
National Convention of Colored Men in Nashville on April 5, 1876, along with Dr. W. H. C. Stephenson,
William R. Gamble (father of Lucy Gamble) and the Rev. W. W. H. Wilson. R. D. Curry, John Lewis, Calvin Montgomery, and P. Hampten were alternates to the
Nashville Convention. One of the most important issues in the meeting was the denunciation of
lynchings, particularly in Louisiana and Mississippi. In May 1876, he was a delegate to the Nebraska Republican Convention.
Afro-American League In late 1889 and early 1890, Chicago's
T. Thomas Fortune called for the organization of local leagues for the purpose of the advancement of blacks which would meet in January 1890 to form the
National Afro-American League. On January 9, 1890, a meeting was held in Omaha to this effect. Overall was elected chairman of the meeting. Other leaders at the meeting were J. O. Adams, Price Saunders, E. S. Clemens,
Cyrus D. Bell, W. B. Walker, Parker,
Alfred S. Barnett, W. G. Woodbey, F. Lewis, Dr. Stephens, Alfonso Wilson, Fed Thomas,
Silas Robbins, and Dr.
Matthew Ricketts. There were disagreements over the local league's constitution. While Adams supported Overall, Ricketts, Walker, and Bell loudly opposed Overall's domination of the writing of the constitution. Ricketts initially opposed the idea that whites could be allowed in the league, fearing they could dominate it, but Walker supported that clause convincingly. There was also a debate over dues. Ricketts, Barnett, and Thomas were selected to be the local league's delegates to the national convention of the league and
Silas Robbins would attend the national convention as a delegate from the Republican Colored Club. Eventually, Ricketts, A. L. Bennet, S. G. Thomas, Robbins, and Overall attended. At the national meeting, Overall served on the Committee on Credentials, Ricketts on the Committee on Permanent Organization and the executive committee, Robbins on the Address Committee, and Thomas as a Sergeant-at-arms. Back in Nebraska later that year, he was elected treasurer of the Nebraska chapter of the league
Omaha's Trans-Mississippi and International Exposition , 1898. In 1897 and 1898, Overall organized a Congress of White and Colored Americans to be held in Omaha during the
Trans-Mississippi Exposition which took place from June 1 to November 1, 1898. Overall worked with John Albert Williams and Cyrus D. Bell to bring a convention of the National Colored Personal Liberty League led by
Henry Clay Hawkings to Omaha August 17, 1898 during the Expo. Governor
Holcomb and Mayor Moores welcomed those in attendance, and Cyrus Bell and J. C. Parker of Omaha and D. Augustus Stroker, J. Milton Turner, and Dr. Crossland played prominent roles as well with
P. G. Lowery supplying music. On August 22, the National Colored Press Association met in Omaha as well ==Electoral politics and organized labor==