Justin Butterfield (1790 – October 23, 1855) served in 1849–1852 as commissioner of the General Land Office of the United States. Appointed to this position in 1849 by the incoming Zachary Taylor administration, he is best known for having faced down, and defeated, another Whig candidate for the same job, Abraham Lincoln. In the General Land Office, he was one of the leading adopters of the railroad land grant system for financing the construction of long-distance railroad infrastructure throughout the United States. He was also one of the foremost Gentile defenders of the rights of the Church of Jesus Christ of Latter Day Saints in Illinois during the final period of Joseph Smith's leadership at Nauvoo.

Justin Butterfield was born in Keene, New Hampshire in 1790. He entered Williams College at age seventeen; a work-study student, he simultaneously studied college-level courses and served as a schoolteacher, as was allowed by the laws of that day. Upon completion of his studies he removed to Watertown, New York, where he read law in the office of Egbert Ten Eyck. At age 22 he was admitted to the bar, and practiced in Adams, New York; New Orleans; and Watertown. He also married Elizabeth Butterfield née Pearce (1795–1863) of Schoharie, New York, and the couple had eight children. As a New York State attorney, Butterfield was a strong defender of civil liberties, acting for two defendants sued in separate cases of libel. Butterfield argued both cases before juries with separate defenses of the principle of freedom of speech. In 1835 the now middle-aged lawyer visited and established a practice with James H. Collins in the fast-growing frontier village of Chicago, and by 1837 he completed his casework in upstate New York.

Butterfield had a colorful practice in New York. During the War of 1812, he obtained a writ of habeas corpus for his client, who was suspected of communicating with the enemy in Canada. He served the writ on the commanding general who was holding his client. The general evaded compliance, and Butterfield was branded as disloyal by the public. During the Mexican–American War he was asked if he opposed that war, replying "No, Sir! I oppose no war; I opposed one once and it ruined me. Henceforth I'm for war, pestilence, and famine!"

Butterfield became one of the pioneer attorneys of Chicago at a time when the village at the foot of Lake Michigan was beginning to establish its supremacy over all of the other settlements of the American Midwest. A legal history of Illinois describes Butterfield as "one of the greatest lawyers of his time" and refers to the partnership of Butterfield & Collins, formed in 1835, as a firm of "very high rank, not only in the city of Chicago, but across the state." He was one of the trustees of Rush Medical College at its incorporation in 1837. In 1841 he was named United States Attorney for the District of Illinois

Butterfield practiced with Collins in 1835–1843, and then with Erastus S. Williams in 1843–1849. He played a key role in helping Illinois businesses, and the State as a whole, work out from under the effects of the Panic of 1837. Specializing in debt restructuring, he and close associates developed legal language in 1843 to refinance the Illinois and Michigan Canal, a work of such magnitude that it had helped to drive the state of Illinois into default. By pledging to Eastern capital the half-excavated canal and much public land owned by the state, Butterfield obtained an emergency loan of $1.6 million, with which a shallow canal could be dug out and completed from Chicago to La Salle, Illinois. Although Illinois taxpayers achieved a less-than-optimal resolution of the state's difficulties, the deal helped Butterfield establish enduring connections with New York bankers.

Butterfield also practiced criminal law. In summer 1843, Joseph Smith, the head of the Church of Jesus Christ of Latter Day Saints, asked Butterfield to defend him in federal court. The Nauvoo leader had been arrested by Missouri peace officers on a variety of charges related to the Mormons' time in that state some years earlier; in order to avoid extradition and possible lynching, Butterfield asked a federal court sitting in Illinois to grant habeas corpus to Smith. When Judge Nathaniel Pope granted this motion, Smith and his lawyer made a spectacular appearance in a Springfield, Illinois courtroom. Unrepentantly admitting to Judge Pope that his client was a fugitive, Butterfield proclaimed the supremacy of federal law over state law (a contested legal doctrine in 1843) and stated that he and his client had appeared in federal court to "plead for liberty, personal freedom, secured to every citizen in this broad land by the Constitution of the United States." During the trial, the gallery had a large number of women. Butterfield's witty opening statement was "May it please your Honor, I appear before the Pope, in the presence of angels, to defend the Prophet of the Lord!"

Although Judge Pope issued a decision on the lines suggested by counsel Butterfield and released Smith upon these terms, the Mormon leader and his close associates began to realize that they could not practice their faith within the boundaries of any of the existing states of the United States. Only the federal government could grant the Latter-Day Saints the space they needed to continue to develop their church. After Smith was killed in June 1844, Brigham Young led most of the surviving Mormons westward towards Utah. Although a Gentile, Butterfield's legal advocacy had played a role in the history of the Latter-Day Saints.

By 1849 Justin Butterfield was a Chicago attorney with strong national connections throughout the then-dominant Whig Party. In November 1848, the Whigs elected Zachary Taylor to the White House, and now had the pleasant task of selecting loyal party political figures to the high-ranking positions of the incoming Taylor administration.