"And then after that, he just kind of exploded," said Dolton.

He wrote songs for the likes of Count Basie, Glenn Miller and Tommy Dorsey. He also penned songs for Broadway musicals, movies and Disney shorts. Gannon was nominated for three Academy Awards. However, like the soldier longing to be home for Christmas, the Gannons were always drawn back to Greenwich.

Kim Gannon and his wife never forgot their community. They left money behind to create a park and a youth center in town.

"They really felt like they were a part of Greenwich," Dolton said.

Crosby recorded Gannon's classic in 1943. Since then, more than 700 artists have done the same, including Michael Buble and Whitney Houston. It's among the top 10 Christmas songs of all time.

Gannon wrote it from the perspective of a World War II soldier longing for home. However, what seems to make it great is that it's so relatable. Anyone who has ever been separated from a loved one at Christmas knows the feeling.

"Even at the end, 'if only in my dreams,' if somebody's passed away, it brings that feeling as well."

The Gannons bequeathed a portion of Gannon's yearly royalties to St. Lawrence University, where both graduated and Kim wrote the alma mater.

According to Dolton, the college has received more than $500,000.