LeMahieu and the Yankees had been negotiating for much of the offseason, with the 32-year-old's agent reportedly seeking a five-year, $100-million contract in early December.
The California native played well for the Yankees after they signed him to a two-year pact before the 2019 season, hitting .336/.386/.536 with 36 home runs, 43 doubles, and 129 RBIs in 195 games.
LeMahieu won the American League batting title in 2020 and finished third in AL MVP voting.
The Atlanta Braves, Boston Red Sox, Los Angeles Dodgers, New York Mets, Toronto Blue Jays, and Washington Nationals had all shown interest in the two-time batting champion this offseason.
The Dodgers reportedly offered the three-time All-Star a four-year deal worth $60 million, while the Blue Jays extended a similar four-year offer valued at $78 million, a source told baseball insider Pat Ragazzo.
LeMahieu was very close to signing with Toronto before accepting the Yankees deal, Ragazzo added.