Manuel P. (Emmanuel) Jackson was born around 1840 in Albemarle County, Virginia. His parents were James and Patcy Jackson, and his brother was Alexander Jackson, who served with him in the 55th Massachusetts Volunteer Infantry Regiment. Jackson was born into slavery, but he was "liberated," in his own words, around 1854 when his family moved to Chillicothe, Ohio. Prior to the war, Jackson worked on his father's farm.

Jackson enlisted as a private at the age of 23 on June 5, 1863, and mustered in on June 15, 1863, in Readville, Massachusetts. His service record describes him as 5 feet, 8 1/2 inches tall, with black hair, brown eyes, and a dark complexion. He served with his brother Alexander in Company G of the 55th Massachusetts, the sister regiment of the famed 54th Massachusetts Infantry Regiment. Jackson served throughout South Carolina and took part in the Battle of Honey Hill on November 30, 1864. Jackson mustered out on August 29, 1865, in Charleston, South Carolina.

Jackson returned to Ohio after the war and lived most of his life in Martinsville. He relocated to a soldiers' and sailors' home in Erie County late in life. Jackson suffered from a spinal disease, and he had to treat himself because he was unable to afford a doctor. He applied for a pension in 1882, and in 1890 he began receiving $12 per month. He died in 1897, probably at the soldiers' home.