Mordecai Oliver was an attorney and two-term U.S. Representative

United States House of Representatives

The United States House of Representatives is one of the two Houses of the United States Congress, the bicameral legislature which also includes the Senate.The composition and powers of the House are established in Article One of the Constitution...

 from Missouri

Missouri

Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

.

Born in Anderson County, Kentucky

Anderson County, Kentucky

Anderson County is a county located in the U.S. state of Kentucky. It was formed in 1827. In 2010 the population was 21,421. Its county seat is Lawrenceburg, Kentucky. The county is named for Richard Clough Anderson, Jr., a Kentucky Legislator, U.S...

, Oliver attended the common schools and then studied law.
He was admitted to the bar in 1842 and commenced practice in Richmond, Missouri

Richmond, Missouri

Richmond is a city in Ray County, Missouri, United States. The population was 5,797 at the 2010 census. It is the county seat of Ray County.-Geography:Richmond is located at...

. He served as a prosecuting attorney for the Fifth Judicial Circuit in 1848.

Oliver was elected as a Whig

Whig Party (United States)

The Whig Party was a political party of the United States during the era of Jacksonian democracy. Considered integral to the Second Party System and operating from the early 1830s to the mid-1850s, the party was formed in opposition to the policies of President Andrew Jackson and his Democratic...

 to the Thirty-third Congress and reelected as an Opposition Party

Opposition Party (United States)

The Opposition Party in the United States is a label with two different applications in Congressional history, as a majority party in Congress 1854-58, and as a Third Party in the South 1858-1860....

 candidate to the Thirty-fourth Congress (March 4, 1853–March 3, 1857).

Oliver was elected as a Unionist

Union (American Civil War)

During the American Civil War, the Union was a name used to refer to the federal government of the United States, which was supported by the twenty free states and five border slave states. It was opposed by 11 southern slave states that had declared a secession to join together to form the...

 Secretary of State

Secretary of State

Secretary of State or State Secretary is a commonly used title for a senior or mid-level post in governments around the world. The role varies between countries, and in some cases there are multiple Secretaries of State in the Government....

 of Missouri in 1861.

He resumed the practice of law in St. Louis, Missouri, and served as judge of the criminal court 1889-1893. He moved to Springfield, Missouri

Springfield, Missouri

Springfield is the third largest city in the U.S. state of Missouri and the county seat of Greene County. According to the 2010 census data, the population was 159,498, an increase of 5.2% since the 2000 census. The Springfield Metropolitan Area, population 436,712, includes the counties of...

, where he died April 25, 1898.
He was interred in Hazelwood Cemetery.