During the Reconstruction Period, he served as secretary of the 1867 Democratic convention. He wrote extensively about politics in Little Rock during this time, keeping newspaper clippings and long commentaries on the articles. His writings were published in 1893 as the "Brooks and Baxter War", and are one of the most prominent sources on the Brooks–Baxter War. In 1899, Harrell and John Dimitry co-authored "Confederate Military History, Volume X: Louisiana and Arkansas".