In the American Civil War, he played a major role in making the Union blockade effective, but was controversially blamed for the failed attack on Charleston, South Carolina in April 1863.

(Samuel was the only member of his generation to use a capital D.)[1] Du Pont spent his childhood at his father's home, Louviers, across the Brandywine Creek from his uncle's estate and gunpowder factory, Eleutherian Mills, just north of Wilmington, Delaware.

He returned to service in 1845 as commander of the Congress, the flagship of Commodore Robert Stockton, reaching California by way of a cruise of the Hawaiian Islands by the time the Mexican–American War had begun.

Du Pont then continued operations along the Baja coast, including the capture of La Paz, and burnt two enemy gunboats in the harbor of Guaymas under heavy fire.

He led the main line of ships that took Mazatlán on November 11, 1847, and on February 15, 1848, launched an amphibious assault on San José del Cabo that managed to strike three miles (5 km) inland and relieve a besieged squadron, despite heavy resistance.

He was an advocate for a more mobile and offensive Navy, rather than the harbor defense function that much of it was then relegated to, and worked on revising naval rules and regulations.

In 1853, Du Pont was made general superintendent over what is typically considered the first World's Fair in the United States—the Exhibition of the Industry of All Nations, held in New York City.

When those under fire called upon friends in Congress, Du Pont himself became the subject of heavy criticism, and subsequent review of the dismissals resulted in the reinstatement of nearly half of those removed.

He played a major role in the receiving of the Japanese ambassador that year, accompanying him on his three-month visit to Washington, Baltimore, and Philadelphia; the trip was a breakthrough for opening Japan to American trade and investment.

[2] When communication was cut off with Washington at the start of the Civil War, Du Pont took the initiative of sending a fleet to the Chesapeake Bay to protect the landing of Union troops at Annapolis, Maryland.

This victory enabled Union naval forces to secure the southern waters of Georgia and the entire eastern coast of Florida, and an effective blockade was established.

Though he commanded them ably in engagements with other ships, they performed poorly in an attack on Fort McAllister, due to their small number of guns and slow rate of fire.

Du Pont was then given direct orders from the Navy Department to launch an attack on Charleston, South Carolina which was the site of the first shots fired in the Civil War with the fall of Fort Sumter and the main area in which the Union blockade had been unsuccessful.

Though he enlisted the help of Maryland U.S. Representative Henry Winter Davis to get his official report of the incident published by the Navy, an ultimately inconclusive congressional investigation into the failure essentially turned into a trial of whether Du Pont had misused his ships and misled his superiors.

In 1882, 17 years after Du Pont's death, the U.S. Congress finally moved to recognize his service and commissioned a sculpture of him to be placed in Pacific Circle in Washington.