At the Summer Olympics held in London in July 1908, owing to the British system of a blind draw for the preliminary heats, he was paired in the 2nd heat with America's other best miler, Mel Sheppard.
Nauseated by an upset stomach just before the heat, Halstead was unable to produce his customary final sprint and lost the heat by a yard to Sheppard in a time of 4:05, thus disqualifying him from the finals.
Halstead upheld the American team's reputation for good sportsmanship by never uttering a word of complaint about the British system of a blind draw.
In the 800 metres, held a week later, Halstead won his first round heat with a time of 2:01.4.
During the latter part of 1908 and 1909, he was one of the engineers who worked on the construction of the Pennsylvania Railroad Station in New York City.