In 1840, Secretary of State John Forsythe appointed William Weaver the first superintending clerk of the census. The elevation of Weaver, a man without statistical experience, to this new position signaled a shift in how the census would be conducted. Although U.S. marshals would remain responsible for enumeration efforts, the process would be more institutionalized.

Weaver was born in 1797 in Dumfries, Virginia. He became a naval officer at 16, serving from 1813 until 1824 and getting wounded before his ship was captured during the War of 1812. After his military service, he used his strong foreign language skills to secure a job with the State Department.

At the State Department, Weaver was secretary to the commission charged with adjusting claims of Spanish citizens on land in the United States. The border between New Spain and the United States, roughly defined by the Adams-Onís Treaty, remained in dispute until the end of the Mexican War. In 1834, he was commissioner to Mexico. He remained at that post until the 1840 census.

As “superintending clerk” of the census, Weaver was responsible for the design of the enumeration schedule, which crammed 80 columns on two-sided questionnaires. The poor design of the schedules led to enumerator error, including significant instances of healthy free blacks being misclassified as insane. Despite this error, John C. Calhoun, who replaced Forsythe as secretary of state when Andrew Jackson was inaugurated in 1841, reappointed Weaver (his initial term as superintending clerk had expired) to report the census results to Congress in 1842, where Weaver actively defended the findings of the 1840 census. Weaver died in his hometown, Dumfries, in 1846.