Cardiopulmonary problems notwithstanding, Sheppard won three consecutive AAU titles in the 880 yards (805 m) from 1906 to 1908 and became a main favorite for the middle distance events at the 1908 Summer Olympics in London.

In the second, about to be beaten again, he threw Haskins to the floor with a flying mare, which he also did to another runner, Adam O'Shea, in the Millrose Games in which he was disqualified.

[4] By May the New York Times reported that Haskins, "unquestionably the best half-mile and mile performer in the country", had been refused selection for the United States team to the 1908 Olympics for which he had been trying.

Sheppard won the 1500 metres, setting an Olympic record at 4:05.0 in the first round that fell in the very next heat, when Norman Hallows ran a 4:03.6.

Even without being in as good of form as he had been in the individual races, Sheppard had little trouble retaining the leads giving to him teammates William Hamilton, Nate Cartmell, and John Taylor.

Sheppard won his fourth gold medal as lead-off runner on the 4×400 metre relay team that set a world record of 3:16.6.

He was survived by his wife Estelle (née) Symon, his daughter Adelaide Kohler of Wildwood, New Jersey and his son Melvin Sheppard Jr., who was on Princeton University's track and cross country teams in 1932.

[8] While it is claimed that "after retiring from sports Sheppard became a lawyer (he was one of the defenders of the Lindbergh child kidnapper Bruno Hauptmann)," this is an Internet myth.

"The Trial of Bruno Richard Hauptmann," by Sidney B. Whipple, originally published by Doubleday, Doran & Co., NY, 1937, makes no mention of Sheppard.