[6] Parker moved to St. Joseph, Missouri between 1859 and 1861, where he joined his maternal uncle's law firm of Shannon and Branch.

When the American Civil War broke out four days after Parker took office, he enlisted in a pro-Union home guard unit, the 61st Missouri Emergency Regiment.

[10] Parker was nominated for Missouri's 7th congressional district on September 13, 1870, backed by the Radical faction of the Republican Party.

During his first term, Parker helped to secure pensions for veterans in his district and campaigned for a new federal building to be built in St. Joseph.

He sponsored a failed bill designed to enfranchise women and allow them to hold public office in United States territories.

[5] However, the political tide had shifted in Missouri; it seemed unlikely that the legislature would elect him to the Senate, so he sought a presidential appointment as judge for the Western District of Arkansas.

[6][10] On May 26, 1874, President Ulysses S. Grant nominated Parker as Chief Justice of the Utah Territory to replace James B.

It had been previously vacated by federal Judge William Story (1843–1921), who resigned under threat of impeachment by the Senate for allegations of corruption.

Clayton subsequently served as the U.S. Attorney for the Western District of Arkansas for fourteen of Parker's twenty-one years tenure on the court.

Reeves knew the Territory well and could speak several Native languages and thus became the first Black / African American deputy marshal west of the Mississippi River.

The Five Civilized Tribes and other Native American tribes assigned in the Indian Territory (originally set up in the 1830s under seventh President Andrew Jackson in the controversial Indian Removal "Trail of Tears" from southeastern states in a far wider amount of territories to the west of the Mississippi River) had jurisdiction over their own citizens / members through their semi-independent tribal legal systems and governments allowed by treaty.

[24][25] According to the policies set up by the United States Congress, the federal court for the Western District of Arkansas was to meet in four separate terms each year: in the months of February, May, August, and November.

[6][7] Finally eight years later, in 1883, the Congress reduced the jurisdiction and territory of the district court, reassigning parts of the Indian Territory to the south and the north borderlands to federal courts in adjacent states of Texas and Kansas (admitted earlier to the Union in 1845 and 1861, respectively); however, the increasing number of European American settlers moving into Indian lands and increased strife and criminal activity in sparsely settled areas still increased Parker and the court's workload.

[7][26] From May 1, 1889, (because of the opening of the newly organized Oklahoma Territory further west and some parts of the Indian Territories to White settlers in the famous Oklahoma Land Rush of 1889 of that earlier April), Congress made changes to allow appeals of capital convictions to go instead to the U.S. Supreme Court in Washington, D.C..[27][28] Forty-four cases in which Parker imposed the death penalty were appealed to the Supreme Court.

[31] Today, this hospital still exists as a medical agency (although affiliated with a different Protestant denomination) as Baptist Health Fort Smith.

[32] In his time on the federal court, Parker presided over a number of high-profile cases, including the trial of Crawford Goldsby, famously known as "Cherokee Bill", and the "Oklahoma Boomer" case involving David L. Payne, a non-Indian who illegally settled on tribal lands in the Indian Territory.

[37][38] A year later in 1895, Congress itself addressed the issue in dispute by passing a Courts Act that removed the remaining Indian Territory jurisdiction of the Western District of Arkansas in Fort Smith and powers of Judge Parker, effective September 1, 1896.

When the August 1896 term began, Parker was at home, suffering from Bright's disease and too ill to preside over the court.

[22] Parker died on November 17, 1896, of a number of health conditions, including heart degeneration and Bright's disease.