Martin Tansey was born around 1843 in Ireland. He immigrated to America around 1847 and settled in Ohio.
He enlisted in the Union army on August 14, 1862, and he mustered in as a private in Company H of the 79th Ohio Infantry on August 23. The regiment took part in the Atlanta campaign, the March to the Sea, and the Carolinas campaign. He was promoted to corporal on February 17, 1863, and he mustered out on June 9, 1865.
He settled in Wayne, Ohio, after the war and earned a living as a farm laborer. By 1870, he owned $2,300 of real estate. He married Adaline Stroup in April 1877, and their son Howard was born around 1880. They moved to Springborough, Ohio, in the 1870s and then to Franklin, Ohio, in the 1880s. He applied for a federal pension in December 1889 and eventually received one. He died in 1906.