A goal on the stroke of half-time from Chilean international striker Humberto Suazo was enough to give Monterrey their first title in the championship for North and Central American and Caribbean clubs.
Mexican clubs have won the last six CONCACAF titles while the United States have not had a victor since L.A. Galaxy in 2000.
It was a bitterly disappointing night for Salt Lake, who sorely missed the influence of suspended captain and midfield general Kyle Beckerman.
Monterrey, held to a 2-2 draw in the first leg, are struggling to make the play-offs in the Mexican league but they showed their quality with an accomplished performance at a venue where Salt Lake had been unbeaten in 37 previous league and cup games.
Jason Kreis's team had not lost at Rio Tinto stadium since May 16th 2009, but they paid the price for a lack of sharpness in attack, with strikers Fabian Espindola and Alvaro Saborio both well below-par.
Espindola wasted an early chance when he screwed a shot wide after bustling into the area and Salt Lake were given a lesson in composure in the box just before the break.
Sergio Santana played a smart interchange with Suazo, slipping the ball to him with the outside of his foot, and the shaven-headed forward made no mistake from close range.
The hosts came out with all guns blazing in the second half but their usually thoughtful and creative midfield approach was sacrificed for a more direct style which Monterrey's defence had little trouble dealing with.
There were some late scrambled attempts from the U.S. team, with their Argentine playmaker Javier Morales blasting wide in the final moments, but the Mexicans held firm to complete their country's 27th triumph since the competition began in 1962.
Monterrey now qualify for the World Club Cup to be held in Japan in December where they will face the winners of the other continental championships.
