Schul posted an extremely impressive outdoor season in 1964, not losing a single race and beating among others Bruce Kidd, Gerry Lindgren, Billy Mills, Bill Baillie, and Bill Dellinger. Schul first broke the American record in the 5000m at Compton, running 13:38.0. Schul did not run in the NCAA Championships that year, as he thought it unfair for a twenty-six-year-old to be running against younger opponents. He won both the US Championship and the separately held Olympic Trials that year. On August 29, 1964, Schul set a new world record for two miles of 8:26.4, eclipsing the previous mark of 8:29.6 by Michel Jazy of France.