He would win the Calder Trophy during his first season with the Bruins after scoring 41 points in 61 games. He would miss nine games late in the season with a knee injury, foreshadowing the injury problems that would plague his career. Prior to Orr's arrival, the Bruins had missed the playoffs for seven consecutive seasons and while they would not make the post-season during Orr's rookie season, they would make the playoffs in every subsequent season of Orr's career in Boston.
Despite only playing in 46 games of the 1967-68 season, Orr would win the first of eight consecutive Norris Trophies. Back on track in 1968-69, he would play in 67 games and top 20 goals for the first time with 21 and total 64 points.
Orr would explode the following season, scoring 33 goals and adding a whopping 87 assists to total 120 points, six short of the league record and become the first and only defenseman to lead the NHL in scoring, which would net him the Art Ross Trophy and be named the winner of the Hart Trophy. The Bruins would advance through the playoffs, eventually winning the Stanley Cup in overtime of Game 4, a goal captured in an iconic photograph of Orr flying through the air in celebration. Following the playoffs, he would be named the recipient of the Conn Smythe Trophy, making him the first player to win four major NHL awards in the same season.
Orr would top his league leading point total from the previous season with 139 points in 1970-71, including a league leading 102 assists, 26 more than the next closest player, and place second in the scoring race behind Bruin's teammate Phil Esposito while winning the Hart Trophy for the second time. Orr would record a plus-minus rating of +124 that season, an NHL record that still stands today.
In 1979, prior to an exhibition game against the Soviet Wings, the Bruins raised Orr's #4 to the rafters of the Boston Garden.