Campbell, whose recovery was slightly behind schedule in August, took part in a captain's practice at Ristuccia Arena in Wilmington, Mass., according to the Bruins' website.
"Seeing him out there today, he's finally smiling, so it's nice to see him and just have him in the room being himself and being part of the team and doing everything with us," Johnny Boychuk said. "It's nice to see and just great to have him back on the ice."
Campbell was injured June 5 blocking a shot during a Pittsburgh Penguins power play. He finished killing the penalty, and after surgery June 10, the prognosis was 6-8 weeks of recovery.
The Bruins begin training camp Sept. 11 and open the season Oct. 3 against the Tampa Bay Lightning at TD Garden.
"There's countless reasons that I look forward to coming back to Boston, but mainly because I know we’re going to have a good team and I know that we're going to be able to compete," Campbell said in August.