James Brason Wheeler, Jr., was born on April 24, 1841, in Cameron, New York, to James B. Wheeler and Malinda Willard. His father was a farmer who owned $11,454 and $1,620 of personal property by 1860. He grew up and attended school in Cameron, New York, and by 1860, he was working as a farm laborer.
He enlisted in the Union army on September 27, 1861, and he mustered in as a private in Company I of the 34th New York Infantry later that day. The regiment took part in the Seven Days’ Battles, the Battle of Antietam, the Battle of Fredericksburg, and the Battle of Chancellorsville. He was promoted to corporal on January 1, 1862, and he mustered out on June 30, 1863. He reenlisted on January 19, 1864, and he mustered into Company F of the 16th New York Heavy Artillery. He was promoted to sergeant on April 9, 1863, and to 2nd lieutenant on February 19, 1865. He mustered out on August 21, 1865.
He returned to New York after the war, and he married Frances M. Gould on April 12, 1866. They had at least five children: Maud, born around 1867; Mabel, born around 1869; Herbert, born around 1871; Lola, born around 1875; and Inez, born around 1882. They lived in Parma, New York, and Wheeler worked as a farmer. He applied for a federal pension in June 1879 and eventually secured one. He moved to Gove County, Kansas, in 1879, before settling in Oskaloosa, Kansas, around 1883. He and his wife got divorced in October 1888, but they remarried in April 1894. He remained in Oskaloosa until at least 1920, and he died there on May 10, 1923.