Bat Masterson's father, Thomas Masterson was born in Canada in 1827. In 1852 Thomas married Catherine McGurk. They established their home in the Parish of St. George in Quebec Province, Canada. On November 26, 1853, Catherine gave birth to their second son, Bertholomiew. His parents nicknamed him "Bat" and he was baptized in the Catholic Church. The family grew quickly and eventually included seven children. In 1861, Thomas moved the family to the United States. During the next decade the Masterson family was constantly on the move in search of good unoccupied farm land. Their slow westward migration took them through upstate New York and Illinois to Kansas. On June 6, 1871, Thomas established a farm in Grant Township, Sedgwick County, Kansas, about fourteen miles from Wichita. At the time, Sedgwick County was effectively the western edge of Anglo-European civilization in North America. To the west was what the early pioneers called "Indian country."
As a youngster, Bertholomiew rejected his baptismal name and adopted a new one - William Barclay. He kept his nickname and signed as either Bat Masterson or W. B. Masterson. His early education was obtained in one room schoolhouses. It was minimal, but he did learn to read and write. Bat helped his father build a sod house for the family and assisted in clearing the land, planting, and harvesting their first crops, but soon thereafter left home with his older brother, Ed, to become a buffalo hunter. He was about 18 years old at the time. Buffalo meat had long been a staple along the frontier and Buffalo tongue and hump were considered to be delicacies throughout the world. Buffalo hides were in great demand for clothing, shoe leather, and power belting for an expanding industrial plant in the East. Ed and Bat were first employed as skinners and stock tenders. The plains were full of Buffalo hunters and in the evenings, after it was too dark to work, they frequently socialized around one or another camp fire. It was here that Bat learned to drink and gamble and where he first met many of the men who would later become important to him, including Wyatt Earp.
In 1872, The Masterson brothers were employed by Raymond Ritter helping to grade a five mile section of rail line to the newly established town of Buffalo City for the Atchison, Topeka & Santa Fe Railroad. In July 1872, A.A. Robinson, chief engineer for the railroad, laid out streets in Buffalo City and the name of the town was changed to Dodge City. In September of that year, the first trains arrived in town, connecting Dodge with the eastern markets. When their contract with Ritter was completed, Ritter left town before paying the Masterson brothers what was owed them. Ed and Bat went back to buffalo hunting, this time for Tom Nixon and Jim White. At the time, Nixon and White were among the most accomplished hunters on the buffalo range. The Nixon/White hunting party was large and the Masterson brothers transitioned from skinners to shooters and they were joined by their younger brother, Jim. During the 1872-1873 season it was estimated that there were over 10,000 hunters on the range and about 75,000 buffalo were killed within seventy miles of Dodge.
Winter on the plains was harsh and in January 1873, the Masterson brothers decided to give up buffalo hunting. Bat remained in Dodge on the fringes of the buffalo trade while his brothers returned to the family farm in Sedgwick. Ed Masterson returned to Dodge in February 1873 and went to work in the Alhambra Saloon. Dodge was a violent city with frequent gun fights and killings. A Vigilance Committee was formed, but that organization was quickly taken over by rough elements in league with the perpetrators of the violence. Major Richard I. Dodge, the commander at nearby Fort Dodge, arrested five of the Vigilante leaders and recommended that a sheriff be elected. Charles E. Bassett was elected as Ford County's first sheriff. On April 15, 1873, Raymond Ritter passed through Dodge via train on his way East. In a very public confrontation, Bat intercepted him and required him to give up the money that he owed.
Bat returned to buffalo hunting in the spring of 1873, but there were far fewer animals in the annual migration and profits were down. That winter he was surprised by five Cheyenne Indians who robbed him of his horses, weapons, and possessions and forced him to flee on foot. In 1874 there were virtually no buffalo left in Kansas. In March 1876 Bat joined a group of other buffalo hunters and headed for Texas, where there were still plenty of buffalo. The area was protected by the Medicine Lodge Treaty of 1867 which reserved the right to hunt buffalo to the Indians. Ignoring the treaty, they set up camp on the Canadian River at Adobe Walls. On June 26, 1874, there were twenty eight men and one woman in camp when a large group of Kiowa, Cheyenne and Comanche Indians attacked. The Second Battle of Adobe Walls lasted several days with the Indians unable to dislodge the buffalo hunters. (Kit Carson fought the first Battle of Adobe Walls in exactly the same location a decade earlier.)
In response to the incident at Adobe Walls, Colonel Nelson A. Miles organized the Indian Territory Expedition in July 1874. Bat Masterson joined the expedition as a civilian scout. In November he worked as a teamster supporting the expedition and the following year returned to buffalo hunting. The hub of military activity at the time was Fort Elliott on Sweetwater Creek. Charlie Rath set up a store five miles from the fort and the tent community that sprang up around it became the headquarters for the buffalo hunters. Bat was a frequent patron of the high life that characterized Sweetwater after dark. On January 24, 1876, Bat was involved in a shooting incident which resulted in the death of Corporal Melvin A. King and a girl named Mollie Brennan. Bat was wounded, but recovered soon thereafter. Who did what to whom is unclear, but many credited Bat with having killed King after he shot Brennan. Bat's wound resulted in a lifelong limp and forced him to use a cane. It became something of a trademark in later years.