During the Civil War, David Pierson, a young attorney, was elected to represent the parish at the Secession Convention called in January 1861 in Baton Rouge by Governor Thomas Overton Moore. Pierson voted against secession and refused, along with several others, to change his "no" vote at the end of the process when asked to do so to make the final tally unanimous.
There was little military action in Winn Parish during the Civil War, but there was a problem with conscripts fleeing into the wooded areas to avoid military duty. The Confederate States Army defeated a Union detachment sent to destroy a salt works in the parish. Winn Parish contributed to the $80,000 raised to build fortifications on the nearby Red River.
After the war, bandits roamed the Natchez Trace or Harrisonburg Road that ran through the lower part of the parish. Among the worst were the West and Kimbrell clan. For seven years they preyed especially on travelers and migrants passing through the area.
In April 1873, white Democrats forming a militia from Winn Parish joined with ex-Confederate veterans from Rapides and Grant parishes against Republican blacks in the Colfax Massacre in neighboring Grant Parish. They attacked freedmen defending the parish courthouse and two Republican officeholders in the aftermath to the disputed gubernatorial election of 1872. Among the 80-150 blacks killed were at least 50 who had surrendered; a total of three white men were killed in the confrontation.
Winn Parish is the home of the former Long family Democratic political dynasty, started by Huey Long. It is the birthplace of three governors of Louisiana. Governor Earl Long is buried in Winnfield in a public square known as the Earl K. Long State Park.
Since 1956, Winn Parish has had three sheriffs named "Jordan." R. Sanford Jordan, a Democrat, served from 1956 to 1976. A second but unrelated Jordan, James Edward "Buddy" Jordan (1942-2012), was the sheriff from 1992 to 2008, when he was defeated by a 10-vote margin by a fellow Democrat, Albert D. "Bodie" Little. Subsequently, A. D. Little was forced from office in 2011 and convicted thereafter on federal drug charges. Cranford Jordan, Jr. (born 1952), a nephew of Sanford Jordan, won the office on his third attempt in the November 2011 general election and took office in July 2012. Cranford Jordan is an Independent.