Daniel Judson Callaghan (July 26, 1890 – November 13, 1942) was a United States Navy officer who served his country in two wars, in a three-decades-long career.

Callaghan served on several ships during his first 20 years of service, including escort duties during World War I, and also filled some shore-based administrative roles.

At the Naval Battle of Guadalcanal, during a surface action against a larger Japanese force off Savo Island, an enemy shell killed Callaghan on the bridge of his flagship, USS San Francisco.

[6] In his first few years of service, he developed a reputation as a conscientious sailor, noted for avoiding heavy alcohol consumption and regularly attending Mass.

Some years later, one of his captains, Joel Pringle, would write: "[Callaghan's] devotion to duty, sound judgment and ability to inspire loyalty in his subordinates have resulted in a constant and steady increase in the efficiency of the above mentioned batteries.

A few months later, he was appointed as commanding officer of Truxtun, but the stress of his trial appeared to have left its mark—at the age of 25 years, his hair had already turned gray.

[7] Following the entry of the United States into World War I, in April 1917, New Orleans escorted cargo ships crossing the Atlantic Ocean.

For forty-eight hours the New Orleans stayed with the stricken vessel hauling it out of danger [and] finally handing it on to tugs from a North Ireland base.

He left Idaho in June 1923, returning to shore duties for two years before taking up the position of first lieutenant on the battleship USS Colorado in May 1925.

[10] In May 1941, during the early stages of World War II, Roosevelt released Callaghan to take command of the cruiser USS San Francisco.

Analysis of the battle led to a rapid improvement in USN techniques for fighting in poor visibility, particularly in adopting combat information centers.

His brother William Callaghan would later become the first captain of the battleship USS Missouri, a vice admiral, and the first commander of the Military Sea Transportation Service.

Callaghan's Medal of Honor citation read: For extraordinary heroism and conspicuous intrepidity above and beyond the call of duty during action against enemy Japanese forces off Savo Island on the night of 12–13 November 1942.

Although out-balanced in strength and numbers by a desperate and determined enemy, Rear Admiral Callaghan, with ingenious tactical skill and superb coordination of the units under his command, led his forces into battle against tremendous odds, thereby contributing decisively to the rout of a powerful invasion fleet and to the consequent frustration of a formidable Japanese offensive.

While faithfully directing close-range operations in the face of furious bombardment by superior enemy fire power, he was killed on the bridge of his Flagship.

His courageous initiative, inspiring leadership, and judicious foresight in a crisis of grave responsibility were in keeping with the finest traditions of the United States Naval Service.

[16][18][c] The second ship was commissioned on August 29, 1981,[17] one of a class named for the four American admirals killed in World War II, and sold to Taiwan just over 20 years later.

^ While this would normally have been grave misconduct, McCandless reportedly did so because: (1) he was intimately familiar with the plan of attack and was afraid that there would be mistakes if command passed on to another ship, and (2) he wanted to prevent news of Callaghan's death reaching the enemy (through radio interception).