Reagan was shot by John W. Hinckley Jr. outside the Washington Hilton on March 30, 1981.
In a column carried by Fox News, Michael Reagan recalled that as the president staggered into George Washington University Hospital, he said, "I don't mean to trouble you, but I'm having a hard time breathing."
When his wife Nancy rushed to his side, he uttered the famous line: "Honey, I forgot to duck."
And as Reagan was wheeled into surgery, the even more famous line to his doctors: "I hope you're all Republicans."
Michael Reagan wrote: "Dad didn't use humor just to get a laugh. He joked, even in critical situations, to defuse the tension and put people at ease. He always thought of others first. That's what great leaders do."
When he arrived at the hospital, his father told him, "Michael, if you're ever shot, make sure you're not wearing a new suit."
Reagan was wearing a brand new suit, which was cut off him and is now on display at the Reagan Presidential Library in California.