He went to the first-ever World Cup in 1930 in Montevideo, Uruguay, as a 20-year-old attacker for Lierse. He also played the 1934 World Cup in Italy and in 1938 in France.  This makes him one of only four players in the world who have participated in all World Cups before World War II. Voorhoof is also the first Belgian player to score at a World Cup. At the 1934 World Cup, he scored two goals for Belgium against Germany in a 5-2 loss. He was top scorer for the Red Devils with 30 goals until Romelu Lukaku broke that record against Japan on 14 November 2017.