Sergeant John Brosnan (July 1, 1846 – August 7, 1921[1]) was an Irish soldier who fought in the American Civil War.

Brosnan received the United States' highest award for bravery during combat, the Medal of Honor, for his actions during the Second Battle of Petersburg in Virginia on July 17, 1864.

[2] While serving as a sergeant in command of his company, Brosnan performed an act of gallantry that earned him the Medal of Honor.

On the morning of June 17, 1864, during the Second Battle of Petersburg, Brosnan responded to the cries of Corporal Michael Carroll, a member of his company who had been wounded by hidden Confederate forces and was lying exposed to heavy enemy fire.

He died on August 7, 1921, and was interred at Holy Cross Cemetery in Brooklyn.