The Brazilians, bronze medallists in Beijing four years ago, booked their place in Saturday’s showpiece match at Wembley after two goals from Leandro and Romulo ended the South Koreans involvement in the tournament.
World Cup-winners on five occasions they may be, but Brazil have never won an Olympic gold medal, an anomaly that they are now strongly favoured to consign to the history books this weekend.
South Korea, who had won through to the last four with a nail-biting penalty shoot-out win over Great Britain last Saturday, never threatened the South Americans in an open game at Old Trafford.
The opening goal came for Brazil on 38 minutes from Vasco Da Gama defender Romulo after South Korea’s Ki Sung-Yueng was dispossessed in midfield.
Oscar surged forward deep into South Korean territory before feeding Romulo whose shot at the near post slipped under goalkeeper Lee Bum-Young.
Brazil all but made the game safe 12 minutes into the second half with a cleverly worked goal.
Marcelo suddenly quickened Brazil’s tempo and found Neymar inside the area, cutting the ball back to Leandro who drilled his low shot beyond Lee.
Leandro then bagged his second of the night seven minutes later, deftly toe-poking his effort into the bottom corner to make it 3-0.
Earlier, Mexico advanced to the first Olympic football final in their history after coming from behind to defeat Asian giants Japan 3-1.
Japan, who had helped eliminate highly-rated Spain in the first round, appeared set to emulate their female counterparts by reaching the final after Yuki Otsu fired them into a 12th-minute lead.
But Mexico hauled themselves back into the contest after 28 minutes when Marco Fabian equalised.
Oribe Peralta then scored midway through the second half to put Mexico into their first Olympic football final, where they will face either South Korea or favourites Brazil for the gold medal.
In the final minute Peralta then released Javier Cortes down the right with a clever backheel and the substitute held off the defence before squeezing his shot beneath Shuichi Gonda in the Japanese goal.