Dr. Samuel Alexander Mudd was born in Charles County, Maryland, on December 20, 1833. He was the fourth of the ten children of Henry Lowe Mudd and his wife, Sarah Ann Reeves. His father owned a large plantation called "Oak Hill" which was approximately 30 miles from downtown Washington, D.C.. Mudd attended Georgetown College before studying medicine at the University of Maryland.
After graduating in 1856, he returned to Charles County where he worked as a doctor before marrying Sarah Dyer, his childhood sweetheart, on November 26, 1857 and buying his own farm at Bryantown, Maryland. They became the parents of 9 children.
Mudd had long been an advocate of slavery and was a supporter of the Confederate States of America during the American Civil War. He was known to associate with Confederate agents. This included John Wilkes Booth, who he met for the first time on 13th November, 1864.
After Booth's assasination of Abraham Lincoln on April 14, 1865, Booth broke his left leg while fleeing the theatre. He and David Herold arrived at Mudd's house the following day. Mudd set, splinted and bandaged Booth's broken leg and arranged for a carpenter to make Booth a pair of crutches.
Mudd was arrested and charged with conspiracy to murder Abraham Lincoln. During his trial Mudd denied recognizing Booth while treating him.
On 1st May, 1865, President Andrew Johnson ordered the formation of a nine-man military commission to try the conspirators. The trial began on 10th May, 1865. Mary Surratt, Lewis Powell, George Atzerodt, David Herold, Samuel Mudd, Michael O'Laughlin, Edman Spangler and Samuel Arnold were all charged with conspiring to murder Lincoln.
On 29th June, 1865, Mudd was found guilty of conspiracy to murder. He missed the death penalty by one vote and was sentenced to life imprisonment. Four of the defendants were hanged at Washington Penitentiary on 7th July, 1865. Mudd and three others were imprisoned at Fort Jefferson.
During an outbreak of yellow fever in 1867, the prison doctor died. Mudd agreed to take over the position.
Note that the expression "His name is mud" is not related to Samuel Mudd as there are much earlier references to it.