The Celtics announced Friday that Hayward has signed his four-year, maximum deal. It comes 10 days after he chose Boston over Utah and Miami in free agency.
Hayward, who will earn about $128 million, was one of the top free agents available and joins a Celtics team that advanced to the Eastern Conference finals last season.
Hayward was an All-Star last season for the Jazz and averaged 21.9 points. He rejoins Celtics coach Brad Stevens, who coached Hayward in college at Butler.
Landing Hayward was not only a coup for the Celtics, but for the Eastern Conference as a whole. This summer has seen Western Conference teams load up to try to defeat the Warriors, and the vast majority of high-profile roster moves have occurred in the East.