Chile, playing without their suspended star midfielder ArturoVidal, were quick to capitalize on major mistakes by Colombia's defence.
Just seven minutes into the match, Juan Cuadrado attempted to clear across from Chile's Jose Pedro Fuenzalida with a header, but instead left the ball for Charles Aranguiz to shoot it into the net from very close range.
Just four minutes after that, Chile's star striker Alexis Sanchez comfortably dribbled a defender inside the box. His long-distance shot was deflected by the post, but the rebound fell to Fuenzalidaand the winger made things 2-0.
The match was suspended for more than two hours at the end of the first half, due to a thunderstorm. It could eventually be completed,although the pitch, with many puddles, hardly contributed to quality play.
In the 57th minute, to make matters worse for Colombia, midfielde rCarlos Sanchez was sent off for a second bookable offence.
Argentina beat the host team, the United States, 4-0 in Tuesday's semi-final to qualify for Sunday's final at the MetLife Stadium in East Rutherford, New Jersey.
In 2015, tournament hosts Chile beat Argentina in the penalty shootout to win the first major football title in their history.
Since then, however, Argentina beat Chile 2-1 away in March in the South American qualifiers for the 2018 World Cup, and again 2-0 on June 6, in the group round of the Copa America Centenario.