George W. Quimby was born on May 19, 1843, in Concord, Vermont, to Roswell Quimby and Sarah W. Hudson. His father was a farmer who owned $300 in real estate in 1850. Quimby enlisted in the Union army on August 28, 1862, and mustered into Company K of the 15th Vermont Infantry on October 22. The regiment helped defend Washington, D.C., from October 1862 until August 1863, and it mustered out in Brattleboro, Vermont, on August 5, 1863.
Quimby married Cordelia D. Gilbert in Concord on December 30, 1868, and they had at least two children: Lola, born around 1875; and Nina, born around 1881. Quimby worked as a farmer in Concord, and he remained there for the rest of his life. He died in Concord on April 20, 1907.