The USA skipper and our number two goalkeeper made it third-time lucky in the tournament having previously finished second and third.
In doing so, Kasey further increased his chances of becoming the USA's number one choice for this summer's World Cup.
He kept his fourth clean sheet in five games as goals from Josh Wolff and Jeff Agoos secured a 2-0 win against Costa Rice at the Rose Bowl in Pasadena, California.
Battling it out with Blackburn's Brad Friedel for the number one spot, Kasey was forced into action just four times in the final but produced the save of the game when he tipped away Wilmer Lopez's close-range effort in the second half.
The victory was the USA's second in the Gold Cup - the championship of the North and Central American and Caribbean region - having won its inaugural year in 1991.
The USA team was comprised mostly of Major League Soccer players. Kasey was one of the few exceptions. Costa Rica were at full strength.
"I wouldn't sell any of these players short, although there are 12 to 15 of our players in Europe. This was a very good team," US coach Bruce Arena said.
"I think winning this gives us momentum as we continue to prepare, and it makes it look more competitive for one of the 23 spots on the (World Cup) roster.
"I hope it gets really tough to pick a team. That would be a nice problem to have."
Kasey Keller lifted the CONCACAF Gold Cup in America on Saturday night.