Thomas Lloyd Burnett, rancher, son of Ruth (Lloyd) and Samuel Burk Burnett, was born in 1871 on the family ranch in Denton County, Texas. When he was four his family moved to Wichita County, where his father established a new ranch headquarters near the future site of Iowa Park and began running his Four Sixes cattle. Tom received his early education in rural schools near the ranch and later at a private academy in St. Louis, Missouri, prior to attending Virginia Military Institute for three years. His first love was the cattle business, and at age sixteen he was sent as a cowhand to help look after his father's herds in the Big Pasture, the vast acreage in Indian Territory that the Burnetts, Waggoners, and other area ranchers had leased from the Fort Sill Indian Agency. There Tom mastered the Comanche language and developed a lifelong friendship with several in the tribe, including Quanah Parker and his family. By that time the ranch's base of operations had been moved to the Red River near the future site of Burkburnett. At age twenty-one, Burnett was elevated to wagon boss, and his ability to manage men and cattle quickly won the respect of the ranch employees.
On October 8, 1891, he married Ollie Lake of Fort Worth. They had one child. During the Spanish-American War in 1898 Burnett served as a captain with the Rough Riders (see FIRST UNITED STATES VOLUNTEER CAVALRY). In April 1905 he, his father, Quanah Parker, and John R. Abernathy staged a famous wolf hunt on the Big Pasture for President Theodore Roosevelt. Following the breakup of the pasture shortly thereafter, Burnett moved his family back to the Iowa Park headquarters, which his father had leased to him along with the Wichita County ranch, after developing the Four Sixes Ranch in King County. By then he had accumulated a sizable herd of his own, and in 1912, on the death of his grandfather Martin B. Lloyd, he inherited a fourth of the Wichita County properties and a large sum of money. About that time Burnett adopted Lloyd's Triangle brand as his own. The oil discoveries in the county further enlarged his fortune. In 1918 Burnett and his wife were divorced, a move that offended his father. When Burk Burnett died in 1922, he bequeathed Tom $25,000 a year and left the bulk of his estate in trust for his daughter, with a third of the income to go to her mother.
As an independently wealthy cattleman, Tom Burnett financed and promoted various rodeos at his Iowa Park Ranch and in Wichita Falls. Many of these featured old family friends from Oklahoma, including several of his Comanche friends, whom he invited to hunt antelope and camp on the ranch. He developed a passion for good cow horses and later bred palominos that he featured in fairs, parades, and rodeos. Between 1923 and 1925 he purchased the Pope and McAdams ranches in Foard County and the old Moon Ranch, formerly owned by the W. Q. Richards estate, in Cottle County. In 1929 he added the YL, a 32,000-acre tract that was originally part of the O X Ranch, near Paducah. In all he owned 449,415 acres, over which he ran from 4,000 to 6,000 head of Hereford stock bearing the Triangle brand during the 1930s. Charlie Hart, longtime Burnett family employee, was hired to oversee this vast enterprise, which had branch headquarters in Iowa Park and Paducah.
On May 3, 1919, Burnett married businesswoman, champion steer roper, and famed rodeo performer Lucille Mulhall, but both were strong-willed and separated after a year. He next married Lydia Sheldon of Electra in 1921 and built for her a new house in Iowa Park, but that marriage ended before the house was completed. His fourth wife, Bernice Fassett, was a widow with several daughters from her first marriage and a member of a neighboring ranch family.
During his later years Burnett grew interested in banking and civic developments. He was a major stockholder in the Iowa Park State Bank and maintained an office there. He also became involved in the civic affairs of Wichita Falls and gave generously to various charitable causes. When the Great Depression hit, he supplied school-lunch funds for needy children and came to the aid of old cowboys who had been hurt economically. In 1938 he made his last purchase by adding the 20,000-acre 7L Ranch, formerly the Dripping Springs pasture of the OX, to his cattle empire. On Christmas Day of that year, when he noticed a group of needy boys on the street at Iowa Park, he took them to a clothing store and had them outfitted entirely. Burnett died of an apparent heart attack on December 26, 1938, and was buried in Highland Cemetery, Iowa Park. He willed all of his estate to his daughter, Anne, who subsequently managed his ranching empire under the name Tom L. Burnett Cattle Company, a major part of the Burnett estates. Mrs. Perry McArthur of Thornton, Washington, filed suit to set aside Burnett's will, claiming to be the daughter of Burnett and Jennie Ho-We-Ah, an Indian woman. Her claim was denied by the Wichita County District Court, and the decision was upheld by the Second Court of Civil Appeals on February 26, 1943. Burnett's home in Iowa Park was given to the city as a library building in 1981 by his granddaughter, Anne Windfohr Sowell.