Which referee officiated the first FIFA World Cup final?

John Langenus officiated the first FIFA World Cup final, Uruguay versus Argentina, in 1930.

Langenus was a Belgian referee selected for the final in Montevideo. Uruguay won 4–2 after trailing 2–1 at halftime, and Langenus became the first official to referee a World Cup final.

The match had unusual logistical details. The two teams reportedly wanted to use different balls, so one ball was used in the first half and another in the second. Langenus also required assurances about transport and safety before accepting the appointment, reflecting the intense atmosphere surrounding the historic match.