Francis M. Lank was born around 1842 in Ohio to John and Elizabeth Lank. His father was a cooper. The family lived in Bloom, Ohio, and his father probably died in the 1850s. The family moved to Dresden, Ohio, in the 1850s, and by 1860, they owned $20 of personal property.
He enlisted in the Union army on October 23, 1861, and he mustered in as a corporal in Company F of the 62nd Ohio Infantry. The regiment took part in the assault on Fort Wagner and the siege of Petersburg. He was promoted to sergeant on December 20, 1862, and he mustered out on August 23, 1865. He died sometime after the war.