Ellsworth was born in Malta, New York, on April 11, 1837. He attended the United States Military Academy at West Point, but he resigned after two years. He then worked as a journalist in Chicago, Illinois.
When the Civil War broke out in 1861, Ellsworth raised the 11th New York Volunteer Infantry Regiment, known as the "Fire Zouaves." The Zouaves were a flamboyant regiment that wore zouave uniforms, which were inspired by the uniforms of the French Army's Zouave regiments.
The 11th New York Volunteer Infantry Regiment was assigned to General Benjamin Butler's Army of the Potomac. On May 24, 1861, the regiment was ordered to occupy Alexandria, Virginia, which was located across the Potomac River from Washington, D.C.
As the Zouaves entered Alexandria, they encountered a Confederate flag flying from the Marshall House, a hotel in the city. Ellsworth ordered his men to remove the flag, and he climbed up the flagpole to take it down himself.
As Ellsworth reached the top of the pole, he was shot and killed by James W. Jackson, the proprietor of the Marshall House. Jackson was immediately killed by a member of Ellsworth's regiment.
Ellsworth's death was a major blow to the Union cause. He was a popular figure, and his death helped to galvanize support for the Union. His funeral was held in New York City, and he was buried in Greenwood Cemetery.
Ellsworth's death also inspired the composition of a popular song, "The Ballad of Ellsworth." The song tells the story of Ellsworth's life and death, and it was sung by soldiers on both sides of the Civil War.
Ellsworth's death was a significant event in the Civil War. It helped to rally support for the Union cause, and it inspired the composition of a popular song. Ellsworth is remembered as a hero of the Civil War, and his memory is still honored today.