Curtis was born in De Peyster, New York. Upon graduating from the Gouverneur Wesleyan Seminary, Curtis became a teacher, lawyer, and postmaster of De Peyster. In the year prior to the Civil War, he was working as a farmer.
Curtis stood an impressive 6' 7" tall and weighed 225 pounds. His enormous size for the time period prompted even Abraham Lincoln to quip, "Mr. Curtis, how do you know when your feet are cold?" His stature became an issue of concern to his family when the Civil War began as they felt he would surely be an easy target for enemy bullets.[1]
His brigade became part of the expedition against Fort Fisher in December 1864. Curtis' brigade was among the few troops to go ashore yet the first attack against Fort Fisher was defeated. He took part in the second attack in January 1865, in which his brigade played a key role in the Union victory. During the fighting a suggestion of entrenching reached Curtis. He angrily grabbed a handful of shovels and threw them over the traverse shouting "Dig Johnnies! I'm coming for you!"[2] Curtis made good on his promise and continued the attack. He was wounded at the head of his brigade and received a full promotion to brigadier general of volunteers and was also received the Medal of Honor. He remained in the army until January 1866, receiving a brevet to major general of volunteers on March 13, 1865.
He wrote a book titled From Bull Run to Chancellorsville, published in 1906. In 1910, he was the assistant inspector general of the National Home for Disabled Volunteer Soldiers.
At the Second Battle of Fort Fisher: the first man to pass through the stockade, he personally led each assault on the traverses and was 4 times wounded.