|Representing the United States|
|1896 Athens||30 m free pistol|
|1896 Athens||25 m military pistol|
Born in 1868, Paine's father was Charles Jackson Paine, who was a general in the Union Army during the American Civil War, and also was the older brother to John Paine. Sumner briefly attended Harvard University before ending up at the University of Colorado School of Medicine, he earned an M.D. but never practiced, instead he went off to Paris, France, to work.
Paine entered all three of the pistol events in the 1896 Games. He, along with his brother John Paine, was disqualified from the rapid fire pistol because their firearms were not of the appropriate caliber.
The Paine brothers used Colt revolvers in the 25 metre military pistol event, these pistols were superior to the arms used by their opponents, and the brothers had little difficulty winning the top two spots. Sumner finished second with 380 points on 23 hits (of 30 shots) to John's 442 points on 25 hits. The next closest shooter (Nikolaos Morakis from Greece) scored only 205 points.
After winning the military pistol, John withdrew from the 30 metre free pistol event, Sumner easily won this event as well, scoring exactly the same number of points (442) as John had to win the military pistol event, he did this on one fewer hit (24), though, in this case, the second place competitor scored 285 points.
In 1901, Paine went home to find his wife in bed with his daughter's music teacher. To ward him away from the house, he shot four times at him, missing each time. He was briefly jailed and charged with assault until the police realized who he was and accepted that he must have missed on purpose. He was then released.
- "Sumner Paine". Olympics at Sports-Reference.com. Retrieved 25 June 2017.
- "Shooting at the 1896 Athina Summer Games: Men's Military Pistol, 25 metres". Olympics at Sports-Reference.com. Retrieved 25 June 2017.
- "Shooting at the 1896 Athina Summer Games: Men's Free Pistol, 30 metres". Olympics at Sports-Reference.com. Retrieved 25 June 2017.
- "Guns and Whiskey - At the Olympics". petticoatsandpistols.com. Retrieved 25 June 2017.
- "Obituary". Chicago Tribune. 19 April 1904. Retrieved 25 June 2017.