The United States President who was not injured in a situation involving a gun was President Gerald Ford. On September 22, 1975, Sara Jane Moore attempted to assassinate Gerald Ford in San Francisco. Moore fired two gunshots at President Ford; both shots missed. Moore had previously been evaluated by the US Secret Service in 1975, but agents decided that she posed no danger to the president.

On the day before the assassination attempt in September, Moore was detained by police on an illegal handgun charge. She was released. The police confiscated a .44 caliber revolver and 113 rounds of ammunition. On the day of the assassination attempt, President Ford was traveling to San Francisco to address the World Affairs Council. In the aftermath, Moore on December 12, 1975 pleaded guilty to charges of attempted assassination. The following month in January, she was sentenced to life imprisonment. In December 2007 at the age of 77, Moore was paroled after serving 32 years.

President Ford died in December 2006 in Rancho Mirage, CA of arteriosclerotic cerebrovascular disease. He had become the longest-lived (93 years and 120 days) president in American history.

Additionally, regarding U.S. history, four sitting U.S. presidents have been killed, all of them by gunshot: Abraham Lincoln (1865), James A. Garfield (1881), William McKinley (1901), and John F. Kennedy (1963).

More Info: en.wikipedia.org