Warner Parsons was born around 1841 in Williamstown, Massachusetts, to Orrin and Florinda Parsons. His father was a laborer. Parsons lived in Adams, Massachusetts, until the 1850s, when he moved to Clarksburg, Massachusetts. He earned a living as a farm laborer there. He married Julia Wilcox on July 25, 1861, and they had at least three children: Ruth, born around 1876; Frederick, born around 1879; and Rufus, born around 1885.
He enlisted in the Union army on July 23, 1862, and he mustered in as a private in Company E of the 37th Massachusetts Infantry. The regiment took part in the Battle of Fredericksburg, the Battle of Gettysburg, the siege of Petersburg, and the Appomattox campaign. He fell ill with chronic diarrhea in early 1864 and spent several months recovering in the hospital in Washington, D.C. He rejoined the regiment in the summer of 1864, and he mustered out on June 21, 1865.
He settled in Franklin County, Massachusetts, after the war, and he worked in a chair shop. His wife died in the early 1920s. He moved into his son Frederick’s household in Greenfield, Massachusetts, around 1925, and he died there on April 4, 1926.