During his career as a judge, he sentenced 160 people (156 men and 4 women) to death by the gallows, 79 were eventually hanged. This circumstance gave him the name "Hanging Judge" one. When ordinary citizens Parker was popular because of its hardness against the condemned. They saw it as the only effective means to prevent the countless criminals at that time to master. In 1875, he stepped in Fort Smith in the court presidency succeeds William Story, since this corruption was transferred. In the 21 years in which he held the office there, 65 U.S. Marshals were killed in the line of duty.
" The certainty of punishment is the only prevention of crime ," Parker was credo.
During his career, he met some " customers" who are also passed into history, it was condemned by him as the famous Belle Starr.
From March 4, 1871 until March 3, 1875 Parker sat as a Republican representative of the state of Missouri in the House of Representatives of the United States.
Isaac C. Parker appears in the Lucky Luke Volume 69 Belle Star.