Samuel Humer was born on March 4, 1839, in Cumberland County, Pennsylvania, to Daniel Humer. His father was a farmer.
Humer served in the 158th Pennsylvania Militia Infantry, which was drafted into federal service in the fall of 1862. The regiment served in Virginia and North Carolina. He express discontent with the Union war effort, encouraging a friend to evade the draft and “let them go that thinks it is a glorous war to free the [n---r].” He apparently blamed abolitionists for provoking the war, and he insisted that “our country is ruined and I fear that they will never lick the south if they fight them ten years. I think the soo[n]er they can mak it up the better it will be for both sides.” Humer mustered out on August 12, 1863.
He worked as a coachmaker in Newburg, Pennsylvania, and by 1870, he owned $800 of real estate and $400 of personal property. He married Mary Mowry in December 1864, and their son Theodore was born around 1865. He applied for a federal pension in March 1892 and eventually secured one. His wife died in the late 1800s, and he lived with his son in Newburg until at least 1920. He died of a brain hemorrhage in Newburg on February 1, 1921.