With that in mind, Bay was among 360 people officially sworn in as a United States citizen in a ceremony at historic Faneuil Hall in Boston on Thursday, an off-day for the Red Sox.
Though Bay isn't likely to run to left field with an American flag like his predecessor Manny Ramirez did after becoming a U.S. citizen in 2004, he expressed enthusiasm about his dual citizenship.
"It's exciting," Bay said recently. "My wife is American and both my girls are American as well. This is where I spend most of my time. Although it is a big deal, it doesn't mean I cease being Canadian. I'll always be Canadian. I understand, for a lot of people, this is a very big deal, and I'm pretty excited."
Bay, 30, spends his offseason in Seattle. His parents still live in Trail.
Why did Bay -- who has been in the Major Leagues since 2003 -- think now was the time to become a U.S. citizen?
"It's just kind of the natural progression. I have my green card, and once you have your green card, the next step is citizenship," said Bay. "Because my family is American and that's where I'm going to be, it just made sense."
Bay came to the Red Sox on July 31, 2008, in a blockbuster trade for Ramirez. Despite his recent slump, he is third in the American League with 19 homers and first with 69 RBIs.
Bay's first game as a U.S. citizen will be Friday night at Fenway Park, when the Red Sox open a three-game series against the Mariners.
David Ortiz, Boston's star designated hitter, became a U.S. citizen last year. Ortiz and Ramirez are both from the Dominican Republic.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.