President Abraham Lincoln signed legislation creating the Secret Service on April 14 , 1865 , the day of his assassination . It was commissioned on July 5 , 1865 , in Washington , D.C. as the " Secret Service Division " of the Department of the Treasury . After being appointed by President Andrew Johnson , William P. Wood was sworn in as the first Chief of the Secret Service on July 5 , 1865 by Secretary of the Treasury Hugh McCulloch
his assassination
Assassination of Abraham Lincoln
Director of the United States Secret Service