Andrew Tomlin was born on March 15, 1845, in Goshen, New Jersey. He enlisted in the U.S. Marine Corps on July 21, 1863, in Philadelphia, Pennsylvania, and served aboard the steam screw frigate USS Wabash during the U.S. Civil War. Corporal Tomlin was awarded the Medal of Honor on June 22, 1865, for his actions aboard the Wabash during the Second Battle of Fort Fisher on January 15, 1865. After returning to New Jersey, he became commissioner of juries in 1880, and sheriff of Cape May County, New Jersey, in 1895. Andrew Tomlin died on November 1, 1906, and was buried at the Goshen Methodist Cemetery in Goshen, New Jersey.

His Medal of Honor Citation reads:

As corporal of the guard on board the U.S.S. WABASH during the assault on Fort Fisher, on 15 January 1865. As one of 200 Marines assembled to hold a line of entrenchment's in the rear of the fort which the enemy threatened to attack in force following a retreat in panic by more than two-thirds of the assaulting ground forces, Corporal Tomlin took position in line and remained until morning when relief troops arrived from the fort. When one of his comrades was struck down by enemy fire, he unhesitatingly advanced under a withering fire of musketry into an open plain close to the fort and assisted the wounded man to a place of safety.