William Robert Lamb, Texas Populist leader, was born on October 21, 1850, in McNair County, Tennessee, one of seven children of John Madison and Parmelia A. (Thomason) Lamb. His father was from Missouri. While he was a boy his family moved to Claibourne Parish, Louisiana, where William's mother died. When his father moved to Arkansas, William was bound out for eighteen months to a local Claibourne Parish man, and when his contract was up he worked for two other men in the parish. In 1869, the year his father died in Bowie County, Texas, William moved to Collinsville, Grayson County, Texas, where he worked as a stationary engineer. In 1871 he moved to Denton County and worked first as a rail splitter and then as a hired hand for area farmers. On October 12, 1873, Lamb married eighteen-year-old Drusilla E. Wilson of Jackson Parish, Louisiana, and began farming on rented land. In July 1876 he took a preemption on land in Montague County adjoining the block on which the town of Bowie was later laid out. He built a log cabin on the land and in 1883 moved his family to it. By March 12, 1891, when his wife died, Lamb had five children. On April 24, 1892, he married Mrs. Elizabeth Mary Greenwood Pepperell.
In Denton County, Lamb had worked in a cotton mill and gin, and in 1886, with thirteen other members of the Farmers' Alliance, he opened a cooperative gin and mill that, according to one historian, collapsed because of lack of access to credit. Lamb apparently was involved in another gin in Salona at about the same time, and in 1898 in Bowie with a third gin and mill and cooperative warehouse. The last subsequently burned. Throughout the period he speculated in land; he sold town lots to help finance the third Bowie gin, mill, and warehouse. As of 1905 he still owned sixty acres of land adjoining Bowie.
A year after he settled his family on his land in Montague County, Lamb was recruited into the Texas Farmers' Alliance by S. O. Daws, the organization's first traveling lecturer. Despite only twenty-five days of formal education, Lamb immediately became president of the Montague County alliance. He was so successful an organizer in his county that the state alliance meeting in October 1885 devised a new office for him, that of state lecturer. His subsequent career in the Farmers' Alliance and then the People's party marked him as a leader in both organizations equal, in Texas, to Charles William Macune, who is much better known. In late 1885 Lamb, a leading proponent of cooperative purchasing and marketing, became the first traveling agent of the Texas Farmers' Alliance, the state representative for all county alliance cooperative-purchasing operations dealing in farm machinery. By early 1886 Lamb had emerged as the leader within the Texas alliance pushing hardest for the organization to cooperate with the Knights of Labor, particularly in the Great Southwest Strike. His experience with manufacturers' opposition to large-scale cooperative purchasing by the alliance, and with Jay Gould's intransigence in the Southwest Strike, led him by the spring of 1886 to advocate involvement of the alliance in politics. Around Lamb grew a group responsible for the Cleburne Demands, an aggressive platform outlining farmers' grievances, which the Texas alliance adopted in its state convention in August 1886. The group's greenback, antimonopoly sentiments reappeared in a number of alliance and third-party platforms, then emerged in final form in the Populists' 1892 Omaha platform.
By 1888 Lamb was active in third-party politics. In the spring of that year he was elected to the national executive committee of the Union Labor party and served as the ex officio chairman of the credentials committee at the national convention. With the support of such alliance radical antimonopoly greenbackers as Harry Tracy, Evan Jones, H. S. P. (Stump) Ashby, Thomas Gaines, and James Perdue, Lamb organized the Union Labor party in Texas in the summer of 1888, served on its state executive committee, and campaigned vigorously for it. The subtreasury plan, introduced to the National Farmers' Alliance and Industrial Union at its December 1889 convention in St. Louis, provided the vehicle by which Lamb and his group moved the alliance into the emerging People's party. Led by Lamb and Perdue, they organized within the NFA&IU a scheme for organizing congressional districts whereby the subtreasury became the alliance's key demand.
By the April 1891 Texas Farmers' Alliance convention in Waco, Lamb and his compatriots were able to persuade the organization to send delegates to the May 1891 Cincinnati convention, held to begin setting up a national third party. Lamb was elected a delegate and appointed in Cincinnati to the national executive committee of the newly formed People's party. Two new third-party groups were also formed at the Waco convention: the Texas Citizens' Alliance and the Texas Reform Press Association. Lamb was elected secretary-treasurer of the first and president of the second. He was already serving on the executive committee of the National Reform Press Association, which had been organized at the NFA&IU convention in Ocala, Florida, in late 1890. Lamb's leadership in founding the Populist party in Texas was recognized when he gaveled to order its founding convention in Dallas, the first in the South, on August 17, 1891. He gave the keynote address and was elected chairman of the state executive committee.
In 1888 he took over publishing and editing the Bowie Labor Sunbeam and used it to push for the organization of a third party in Texas. In 1889 the paper's name was changed to Bowie Independent, in 1890 to Montague County Independent, and finally to Texas Independent in 1891. In the fall of 1891 Lamb was sued for libel by a local Democratic politician because of an advertisement run in the paper and written by a local alliance man. He lost and was fined $200, despite his absence at the time the advertisement was accepted and run, his public retraction, and his offer of the Texas Independent's columns to the plaintiff.
Lamb was elected by the Texas Populist convention to the February 1892 national convention of the People's party. He was elected by state conventions to the Omaha national nominating convention of July 1892 and to the 1896 Populist national convention at St. Louis. His role in the party, however, was never very prominent after 1891, and after 1896 he served in no official capacity. He returned to farming and remained "politically radical," according to one historian. He died on April 5, 1933, in Fort Worth, on a visit to his son. He was survived by his second wife, Elizabeth Mary, two sons, and two daughters.