The 34-year-old utility man agreed to a minor league deal with the team Friday. Hill's new pact includes an invitation to spring training.
The Atlanta Braves and Kansas City Royals were previously rumored to have interest in the free agent. Hill hit .262 with 10 home runs and 38 RBI in 125 games last season for the Milwaukee Brewers and Boston Red Sox.
Multiple reports state that Hill will make $2 million next season if he makes the Giants' big league roster. He could also cash in on an additional $1.425 million in incentives and performance bonuses, according to MLB Network Insider Jon Heyman.
After being selected with the No. 13 pick in the 2003 amateur draft, Hill played seven seasons for the Toronto Blue Jays. He earned an All-Star nod in 2009 while hitting .286 with 36 home runs and 108 RBI. Hill led Major League Baseball that season with 734 plate appearances and 682 at-bats.
He was traded to the Arizona Diamondbacks in 2011, before being traded again last January to the Brewers. He was traded again in July to the Red Sox. Hill earned $12 million last season, with $6.5 million being paid by the Diamondbacks.
Last season Hill played 103 games at third base and 24 games at second base.