John Logan, the eldest of eleven children, was born in Murphysboro, Jackson County, on 9th February, 1826. After attending local schools he joined the United States Army and saw action in the Mexican War and eventually reached the rank of lieutenant.
In 1849 Logan returned to Illinois where he became the clerk of the Jackson County Court. He studied law and was admitted to the bar in 1852. The following year he became prosecuting attorney for the third judicial district of Illinois.
A member of the Democratic Party, Logan was elected to the 36th and 37th Congresses but resigned in April, 1862, in order to join the Union Army. After taking part in the battle of Bull Run he was commissioned as a colonel of the 31st Illinois. During the Vicksburg campaign he commanded the XV Corps.
In July, 1864, Abraham Lincoln appointed Logan commander of the Army of Tennessee. After objections by Major General William Sherman, Logan was removed from this post. According to Logan, Sherman was prejudiced against soldiers who had not attended West Point.
Elected to the 40th Congress, Logan, now a member the Republican Party, objected to Johnson's attempts to veto the Civil Rights Bill and the Reconstruction Acts. Logan became a member of the Radical Republicans and voted for the impeachment of Johnson in 1868.
Logan lost his seat in 1877 but after working as a lawyer in Chicago for two years he returned to Congress for the 47th and 48th Congresses and was chairman of the Committee of Military Affairs (1879-1886). John Logan died in Washington on 26th December, 1886.