Buckey O ' Neill William Owen " Buckey " O ' Neill ( February 2 , 1860 – July 1 , 1898 ) was an American soldier , sheriff , newspaper editor , miner , politician , gambler and lawyer , mainly in Arizona . His nickname came from his tendency to " buck the tiger " ( play contrary to the odds ) at faro or other card games . Early life . O ' Neill was born on February 2 , 1860 , either in St . Louis , Missouri , or Washington , D . C . , although he sometimes listed Ireland as his birthplace . This last is doubtful , since his parents had been in the United States since the 1850s . During the Civil War , his father , John , served as a captain in the 116th Pennsylvania Volunteers of the Irish Brigade , and was severely wounded at the Battle of Fredericksburg . Tombstone . In 1879 , O ' Neill left home , heading for Arizona Territory . In 1880 , he settled in Tombstone , Arizona . During this time the Earp Brothers , the city policemen , and the Clanton - McLaury Gang , a group of rustlers and murderers , were at war with each other . O ' Neill joined the " Tombstone Epitaph " ; since it was a pro - Earp newspaper , he frequently talked with , and became a casual acquaintance of , the Earps . On October 26 , 1881 the war escalated with the Gunfight at the O . K . Corral . O ' Neill may have been the man to report on the scene . He left Tombstone shortly after , heading for Prescott , Arizona . Prescott . O ' Neill arrived in Prescott in the spring of 1882 . There he rapidly progressed in his journalistic career . Starting as a court reporter , he soon founded his own newspaper , " Hoof and Horn " , a paper for the livestock industry . He became captain of the Prescott Grays in 1886 , the local unit of the Arizona Militia . On February 5 , 1886 , Dennis Dilda , a convicted murderer , was hanged . O ' Neill and the Prescott Grays stood honor guard for the event . When the trap dropped , O ' Neill fainted , which caused him severe embarrassment . He later wrote a story called " The Horse of the Hash - Knife Brand . " In it , a member of a posse admits to nearly fainting at the hanging of a horse thief . In April 27 , 1886 , he married Pauline Schindler . They had a son , but he died shortly after being born premature . In 1888 , while serving as Yavapai County , Arizona judge , he was elected county sheriff , running on the Republican ticket . On March 20 , 1889 , four masked men robbed the Atlantic and Pacific Railroad passenger train in Diablo Canyon . A four - man posse , made up of O ' Neill , Jim Black , Carl Holton , and Ed St . Clair , was soon formed and they took off after robbers . On March 21 , O ' Neill and his posse caught up with the robbers . After exchanging rifle shots , the posse captured the four men . During the fight , no men were injured , but O ' Neill ' s horse was killed . The four men were William Sterin , John Halford , Daniel Harvick , and J . J . Smith . All four were sent to the Yuma Territorial Prison , but were pardoned eight years later . In 1898 , William Sterin enlisted in the Rough Riders under the name Henry Nash , posing as a school teacher from Strawberry , Arizona . He served as a Sergeant under O ' Neill , although the latter was unaware of his past . After his term was up , O ' Neill was elected unanimously Mayor of Prescott . In 1894 and 1896 he ran for Delegate to the United States House of Representatives from Arizona Territory , running on the Populist Party ticket . One of his best friends was Tom Horn . Rough Riders . In 1898 , war broke out between the United States and Spain . O ' Neill joined the Rough Riders and became Captain of Troop A . First Lieutenant Frank Frantz served as O ' Neil ' s Deputy Commander . Along with Alexander Brodie and James McClintock , he tried to make an entire regiment made up of Arizona Cowboys . Eventually though , only three troops were authorized . The Rough Riders landed at Daiquirí on June 22 , 1898 . Two Buffalo Soldier s , of the 10th Cavalry fell overboard . Upon seeing this , O ' Neill jumped into the water in full uniform and sabre . He searched for the men for two minutes , before having to come up for breath . On June 25 , 1898 , the Rough Riders saw their first action . O ' Neill led his men at the front of the line in the Battle of Las Guasimas , capturing the Spanish flank . During the action he saw several men , whom he believed were Spaniards , across the road from him , and shouted " Hostiles on our right , fire at will ! " He learned after the firing ceased that the men he exchanged shots with were Cuban rebels . Death . On July 1 , 1898 , at about 10am , the Rough Riders and the 10th Cavalry were stationed below Kettle Hill . The Spaniards , who were on top of the hill , poured machine gun and Mauser fire down on the Americans . Buckey O ' Neill was killed in action . Theodore Roosevelt , commander of the Rough Riders , wrote about the death of O ' Neill : He is buried in Arlington National Cemetery , Section 1 , Site 294 . On July 3 , 1907 , a monument by sculptor Solon Borglum was dedicated to O ' Neill and the other Rough Riders in their memory in Prescott , Arizona . Seven thousand people gathered to witness the unveiling . Movies . Bucky ( sic ) O ' Neill is a main character in the TNT movie " Rough Riders " , portrayed by Sam Elliott