The left wing recorded his first career hat trick, and with an assist, he also recorded the first four-point contest in his second NHL season.
His power-play goal at 5:08 of the third period gave Boston a 4-3 lead. He assisted on David Krejci's tally at 14:22 of the third.
Defenseman Dennis Wideman and center Marc Savard added two assists apiece, while goaltender Manny Fernandez yielded four goals on 32 shots for the Bruins, who snapped a three-game losing streak.
Atlanta's Slava Kozlov, Mathieu Schneider and Ilya Kovalchuk all had a goal and an assist.
Jason Williams scored once. Colby Armstrong had two assists, while netminder Johan Hedberg was beaten five times on 33 shots in the Thrashers' third straight defeat.
On the power play, Atlanta went 3-for-4 and Boston went 2-for-5.
Swim Week Miami Beach 2014 [PHOTOS]