Oribe Peralta opened the scoring in the 36th minute before Pulido hammered home a rebound at 45 minutes followed by two more goals in the 86th and 89th minutes.
The victory gives Mexico the win in the first of three Brazil 2014 warm-up games in the USA.
The South Koreans were coming off a 1-0 victory on Saturday in Los Angeles over Costa Rica.
This marked Mexico's sixth all-time win over South Korea to go with three losses and two draws.
South Korea will play in Group H alongside Belgium, Algeria and Russia in Brazil.
Mexico are in Group A along with hosts Brazil, Croatia and Cameroon.