Sculptor. His best-known work, a bronze equestrian statue of Andrew Jackson (modeled 1847–48), demonstrates the conceptual boldness and technical ingenuity that sustain his reputation. As the centerpiece of Lafayette Park in Washington, D.C., facing the White House, it remains among the most prominent monuments in the capital city. Although it was the nation's first equestrian statue, Mills devised a daring and technically challenging pose, with the horse rearing on its hind legs. One of the earliest monumental bronzes cast in the United States, it was unveiled in 1853 to great acclaim for its novel design and dynamic effect, despite its stubby proportions and contrived simulation of movement. After learning the technique from books and experiencing several failures, Mills successfully cast the work himself in a foundry he built. Mills was born in or near Syracuse, New York, orphaned early, and indifferently educated. In 1830 or the following year he settled in Charleston, South Carolina. There he worked as a house plasterer until taking an interest in sculpture around 1835. By the early 1840s he was finding some success with portrait busts, first in plaster and then in local stone. While planning for study in Italy, he visited Washington, D.C. There in 1847, although he had never seen an equestrian statue, he was commissioned to prepare a life-size model for the Jackson memorial. After completing this in Charleston, in 1848 he won the contract for the statue and moved to the nation's capital. Following its successful completion, Mills purchased land just north of Washington, where he erected more substantial studio and foundry facilities. Soon he received a congressional commission for an equestrian George Washington, placed in Washington Circle in 1860. Because of his technical expertise, in that year also he was commissioned to cast the deceased Thomas Crawford's enormous Statue of Freedom, placed atop the U.S. Capitol dome in 1863. During the rest of his career, Mills specialized in portrait busts. He died in Washington.