Hayward, 29, fractured the fourth metacarpal in his left hand during the Celtics' 135-115 win over the San Antonio Spurs on Saturday.
The Celtics confirmed the surgery on Monday and are set to be without Hayward until late December.
"Boston Celtics forward Gordon Hayward underwent successful surgery today to repair a fourth metacarpal fracture in his left hand," a Celtics statement read.
"The injury occurred during Saturday night's game against the San Antonio Spurs.
"He is expected to return to play in approximately six weeks."
Hayward is averaging 18.9 points, 7.1 rebounds and 4.1 assists for the Celtics this season.