Internationally, Pešek played 44 matches over a span of 11 years for the national football team, scoring one goal.

Of note, the Czech football team actually made the finals of the 1920 Olympic tournament (presumably guaranteeing them at least a silver medal), but were disqualified from the competition after walking out late in the first half to protest the officiating.

[2] Had the Czech football team not disqualified themselves from the gold medal match in 1920, Pešek would have been the first athlete in history to medal in both a Summer and Winter Olympic sport (a feat achieved only six times since the first Olympic Games in 1896) Pešek started his playing career as a left back, but changed to center half, a position he played for most of his career.

A midsized footballer, he was not tall but particularly strong, he was an outstanding athlete (as evidenced by him playing two Olympic sports) and was known for his great physical endurance.

Pešek retired completely from sports in 1934, working for the Czechoslovakian Health Ministry until being fired in the early 1950s for not being a member of the Communist Party.