quality:corruption, structural:reformatting, quality:correction, linguistic:paraphrasing
Congressman (1848–1849)

In November 1848, Congressman David S. Jackson, a Democrat, of New York's 6th district was unseated for election fraud. Jackson's term was to expire in March 1849 but, during the 19th century, Congress convened annually in December, making it important to fill the seat. Under the laws then in force, the Whig committee from the Sixth District chose Greeley to run in the special election for the remainder of the term, though they did not select him as their candidate for the seat in the following Congress. The Sixth District, or Sixth Ward as it was commonly called, was mostly Irish-American, and Greeley proclaimed his support for Irish efforts towards independence from the United Kingdom. He easily won the November election and took his seat when Congress convened in December 1848. Greeley's selection was procured by the influence of his ally, Thurlow Weed.

As a congressman for three months, Greeley introduced legislation for a homestead act that would allow settlers who improved land to purchase it at low rates—a fourth of what speculators would pay. He was quickly noticed because he launched a series of attacks on legislative privileges, taking note of which congressmen were missing votes, and questioning the office of House Chaplain. This was enough to make him unpopular. But he outraged his colleagues when on December 22, 1848, the Tribune published evidence that many congressmen had been paid excessive sums as travel allowance. In January 1849, Greeley supported a bill that would have corrected the issue, but it was defeated. He was so disliked, he wrote a friend, that he had "divided the House into two parties—one that would like to see me extinguished and the other that wouldn't be satisfied without a hand in doing it."

Other legislation introduced by Greeley, all of which failed, included attempts to end flogging in the Navy and to ban alcohol from its ships. He tried to change the name of the United States to "Columbia", abolish slavery in the District of Columbia, and increase tariffs. One lasting effect of the term of Congressman Greeley was his friendship with a fellow Whig, serving his only term in the House, Illinois's Abraham Lincoln. Greeley's term ended after March 3, 1849, and he returned to New York and the Tribune, having, according to Williams, "failed to achieve much except notoriety".