As a student of Benjamin Henry Latrobe
in Philadelphia, Robert Mills gained a thorough knowledge of the Classical Revival and became a sought-after, if not commercially successful, architect whose monuments, courthouses, residences, and churches illustrate his adept handling of the popular Greek Revival. Born in Charleston, SC, Mills received training in the office of James Hoban
for approximately two years (c. 1800-1802) before moving to Philadelphia and beginning his association with Latrobe. His nearly 10-year relationship with Latrobe made the most lasting impact on the young architect, perhaps even more than his contact with Thomas Jefferson, who generously lent him pertinent architectural books and from whom he sought a recommendation in 1808 as he prepared to launch his own office. By 1809 Mills was engaged on the first of several Philadelphia commissions, the speculative Franklin Row (South 9th Street, between Locust and Walnut, 1809-1810). Other important Philadelphia commissions would follow: Washington Hall (1809; 1814-16); Sansom Street Baptist Church (1811-1812); the State House wings (Independence Hall, 1812); Octagon Unitarian Church (1812-1813); and, demonstrating his engineering skills, the Upper Ferry Bridge covering (1813-1814). During this time in Philadelphia he also was accepted into the St. Andrew's Society and the Society of Artists of the United States (later the Columbian Society of Artists), and his works were regularly exhibited at the Pennsylvania Academy of the Fine Arts.
Mills's ambitions would take him beyond Philadelphia, however. Although he continues in Philadelphia city directories through 1817, he had, in fact, moved to Baltimore in 1815. There he would design the Washington Monument, a preface to his Monument for Washington, DC, as well as St. John's Episcopal Church, the Maryland House of Industry, and the Maryland Club, in addition to a few residences. Apparently always in a straitened financial state, Mills would leave Baltimore in late 1820, using the often-quoted letter in which he declares "the state of business in my profession have put it entirely out of my power to support my family" (Letter to Robert Gilmor, 30 October 1820, Maryland Historical Society). Complaints aside, by 1820 Mills had achieved the national reputation which would carry him back to South Carolina, and also to Richmond, VA, and Washington, DC. By December 1820 he had been appointed by the South Carolina Legislature to its Board of Public Works. By the end of 1822 he was serving as Superintendent of Public Buildings for the State of South Carolina, and from 1824 to 1828 Mills compiled an atlas and statistical treatment for South Carolina while maintaining an active private practice that concentrated on public buildings. By the late 1820s work in South Carolina had thinned, and Mills once again became an itinerant architect, keeping himself busy with a survey of the planned canal along the Susquehanna River.
Hoping to find more work, Mills moved to Washington, DC, in 1830. There he initially occupied himself with alterations to several public buildings, including the Capitol and the Executive Office Buildings, but gradually more lucrative and high profile federal commissions came his way, including those for several marine hospitals and customs houses. In 1836 he won the competition for the Washington National Monument (built 1848-1884) and was also appointed Architect of the Public Buildings, a position from which he designed the Old Post Office (1839-1842), among several others.
In 1842 the designation Architect of the Public Buildings ceased, but Mills remained in Washington, with his commissions slowly decreasing until 1851, when he was replaced as architect for the enlargement of both the Patent Office and the U. S. Capitol by his rival Thomas Ustick Walter.
As a practitioner of the Greek Revival and a promoter of fireproof buildings, Mills exemplifies a period in the history of the United States when a desire for a uniform and identifiable public style played a considerable role. Armed with an engineering and architectural training gained from Latrobe, Mills met this challenge, populating major cities of the Middle Atlantic and southern states with a prototype for public building style which would remain popular well beyond the early nineteenth century. Unfortunately for many scholars of the works of Mills, Latrobe's ringing denunciation colors the public view of him: "Mills is a wretched designer . . . He is a copyist and fit for nothing more!" (Latrobe to Maximilian Godefroy, 10 October 1814, The Correspondence and Miscellaneous Papers of . . . Latrobe, v.3, p. 580, and quoted in Mills Lane, Architecture of the Old South: South Carolina, p. 179, see References).