In a single bold stroke, the Yankees fill a center field void and gain an outstanding lead-off hitter while weakening their longtime rival, Newsday reported.
"New York came after me aggressively and that's what sealed the deal," Damon told WBZ-TV, Boston, Tuesday night.
Boston had offered $40 million and Damon had complained the Red Sox were dragging their feet on a new contract, Newsday said. The $52 million Yankees' pact is subject to a physical and includes a no-trade clause.
Damon told Newsday earlier that he would cut his long hair and shave his beard for the Yankees.
"George Steinbrenner has that policy for a reason, and you have to respect that," Damon said.
Damon hit .316 in 2005 with 10 homers, 75 RBIs and 18 stolen bases in 19 attempts. He has hit .290 over his four-year career.