Benjamin Franklin Powelson was born on September 10, 1840, near Romney, Virginia (present-day West Virginia), to Charles and Katherine Powelson. His father was a farmer. The family moved to Cross Creek, Pennsylvania, in the 1840s, and Powelson attended school there before enrolling at Washington and Jefferson College. He graduated in 1860. He enlisted in the Union army on September 4, 1862, and mustered in as a sergeant in Company K of the 140th Pennsylvania Infantry later that day. The regiment took part in the Battle of Chancellorsville, the Battle of Gettysburg, and the Overland Campaign. He was wounded in the legs in the Battle of Spotsylvania Court House on May 12, 1864.
On October 8, 1864, army officials promoted him to 1st lieutenant in the 41st USCT Infantry. The regiment participated in the siege of Petersburg and the Appomattox Campaign, and he mustered out on January 17, 1866. He was ordained as a minister in 1868. He married Mersylvia Austin around 1870, and they had twelve children, including: Charles, born around 1873; John, born around 1876; Timothy, born around 1878; Pearl, born around 1880; Bertha, born around 1882; Roxie, born around 1884; Leora, born around 1886; Philip, born around 1888; and Joseph, born around 1890.
By 1870, they were living in Deepwater, Missouri, and Powelson owned $1,000 of real estate and $500 of personal property. A decade later, they were living in Greenfield, Missouri, and they moved to Kansas sometime in the 1880s. He applied for a federal pension in November 1890 and eventually secured one. They moved to Grand Junction, Colorado, around 1890 before settling in Gunnison, Colorado, around 1895 and finally Boulder, Colorado, around 1900. Powelson played an active role in veterans affairs, serving as senior vice commander of the department of Colorado and Wyoming. He died in Boulder on April 3, 1914.