Eubulus H. Brigham was born on January 10, 1843, in Waverly, New York, to Edward and Clarissa Brigham. His father was a hotel keeper and merchant who owned $2,000 of real estate and $2,000 of personal property. They moved to Sheshequin, Pennsylvania, in the early 1850s, and by 1860, Brigham was working as a farm laborer. He enlisted in the Union army on August 30, 1862, and mustered in as a private in Company F of the 35th Pennsylvania Infantry later that day. According to his service records, he was 5 feet, 10 inches tall, with dark hair and grey eyes. He was discharged for disability on March 22, 1863.
He moved to Dryden, New York, after leaving the army. He re-enlisted on September 3, 1864, and mustered in as a private in the 1st New York Veteran Cavalry. He mustered out again on June 8, 1865. Brigham returned to Sheshequin after the war and worked as a farmer. He married Wealtha Smith around 1870. He applied for a federal pension in June 1885, complaining of a lung ailment, and he eventually secured one. He moved to Ulster, Pennsylvania, in the 1910s, and he died there of “intestinal grippe” on December 31, 1923.