William Riley Curtis was born about 1845 in Jacksboro, Texas, where he grew up a ragged orphan and learned self-sufficiency at an early age but was denied the education he coveted. He worked for several years learning the cattle business from William S. Ikard. He earned some of his first money riding for Oliver Loving, driving herds to Shreveport, Louisiana, and up the Chisholm Trail to Kansas. For a time he served as a Texas Ranger. He married Alice V. Ghormley of Weatherford on May 18, 1869; they made their home in Jacksboro. To their union were born three sons and a daughter.
In 1870 Bill Curtis and his younger brother, Jim C., purchased Mose Dameron's small herd of Diamond Tail Ranch cattle. They grazed this herd along Cache Creek near Fort Sill after securing a government contract to sell beef to Fort Reno and Fort Sill in the Indian Territory. Soon they accumulated enough wealth to build up ranches on both Cache Creek and the Wichita River. After the expiration of the contract compelled them to seek other pastures, the Curtises established their ranch headquarters near Cambridge in Clay County. There Bill was dealt a severe blow with the accidental death of his brother in 1878. At the same time, he realized that his land was too crowded for good grazing and therefore moved his cattle north to Grosebeck Creek, near the site of present Quanah.
Curtis formed a new partnership with Thomas J. Atkinson, one of a family of Jack County pioneers. With the help of a cowboy, Sam Bean, the partners early in 1879 selected for their headquarters a site on Gypsum Creek, in southeastern Childress County. Later they moved this new headquarters to the junction of Doe and Buck creeks in Collingsworth County. Since their families resided in Henrietta, where the children had better educational opportunities, the partners never constructed a permanent ranchhouse. However, the Curtis and Atkinson families enjoyed summers on the ranch; the Atkinsons brought their own hired nurse and trail cook, along with appropriate camping equipment. Over the next few years Curtis secured more government contracts for reservation beef sales and delivered herds to the Kansas markets.
In the early 1880s George Loving, son of Oliver Loving, made a proposition whereby Curtis could sell out to British capital for a handsome sum and Loving himself could make a $100,000 commission. Curtis accepted, the contract was drawn up, and Loving went to Scotland to form a company and bring back prospective investors to see the Diamond Tail. Despite the ranch's crude living conditions, the Scotsmen were impressed and offered Curtis $1.25 million for the place, which he accepted. Before the deal could be completed, however, Curtis was indicted for shooting a lawyer from Henrietta who tried to kill him. Although he was acquitted, this turn of events caused the Scotsmen to call off negotiations. Due to their initial lack of trust, Curtis later turned down a second offer from Scotland, proposing that he retain one-quarter interest and manage the ranch himself. George Loving lost his commission, and the Diamond Tail remained in the possession of Curtis and Atkinson.
Curtis was widely known for generosity. After Giles emerged as the Diamond Tail's main shipping point with the arrival of the Fort Worth and Denver City Railway in 1887, Curtis began hosting an annual barbecue. A highlight of that event was his presentation of a baby carriage to every baby named for him during that year. When the lean years of the late 1880s caught up with Curtis, he brought in Sam Lazarus, a man with remarkable financial skills, as a receiver to put the ranch in the black again. On February 11, 1893, when a blizzard swept across the Panhandle, Curtis saved the Diamond Tail cattle by riding ahead of them in a heavy Arctic suit. With a pair of wire clippers he cut every fence in his path, allowing the herd to pass through and find safety. Beginning in 1895, Curtis moved most of his cattle to Chavez County, New Mexico. His oldest son, Jim, managed the cattle there and bought out several smaller ranches. Curtis, in the meantime, bought and sold whole herds at Amarillo, holding them on open range near the numerous playas until sold and then shipping them out to the buyers by rail.
On December 1, 1901, Curtis and W. H. Harrell, an Amarillo cattleman and longtime friend, caught the Fort Worth and Denver City train from Amarillo to Memphis, Texas, on business. While making their way to the diner as the train neared Giles, Curtis jostled a passenger whose gun dropped to the floor and discharged accidentally, giving Curtis a fatal wound. A special train from Clarendon rushed him to Fort Worth, but he lived only a few days. The president of the FW&DC road, who was a friend of Curtis, ran a special train to Henrietta to bear the body home for burial. Curtis's last request to his family was complete forgiveness for the careless man whose gun had killed him. For many years the Curtis children and their families continued ranching activities in New Mexico, and some of them made their homes in Amarillo, where their heirs still reside. Several years after Curtis's death, George L. Rickard, a one-time Diamond Tail cowboy since grown rich, used the brand on his herd of 50,000 head in South America as a tribute to his former boss.