On November 22, 1963, Smith was the main UPI reporter in Dallas for John F. Kennedy's visit. He traveled in the motorcade in the White House Pool car, which had a radiotelephone. When the shots were fired, Smith grabbed the phone and called the UPI office. He stayed on the phone while Jack Bell, the AP reporter in the car, started punching Smith and yelling at him to hand the phone over. At 12:34 PM CST, four minutes after the presidential shooting, the report went out over UPI wire. In 1964, he won the Pulitzer Prize for his coverage of the assassination of US President John F. Kennedy. He was the first to publicly use the term "grassy knoll" regarding the assassination.