In his rookie season (1979–1980), Bird immediately transformed the Celtics into a title contender. The team improved its win total by 32 games from the year before he was drafted and finished first in the Eastern Conference. In his career debut, Bird recorded 14 points, 10 rebounds and 5 assists in a 114–106 win over the Houston Rockets. On November 14, 1979, Bird recorded his first career triple-double with 23 points, 19 rebounds and 10 assists in a 115–111 win over the Detroit Pistons. On November 23, Bird recorded his first 30-point scoring game (along with 11 rebounds and 3 assists) in a 118–103 win over the Indiana Pacers.
With averages of 21.3 points, 10.4 rebounds, 4.5 assists, and 1.7 steals per game for the season, he was selected to the All-Star Team and named Rookie of the Year. In the Conference Finals, Boston was eliminated by the Philadelphia 76ers.
Before the 1980–81 season, the Celtics selected forward Kevin McHale in the draft and acquired center Robert Parish from the Golden State Warriors, forming a Hall of Fame trio for years to come; the frontcourt of Bird, McHale, and Parish is regarded as one of the greatest frontcourts in NBA history. Behind Bird's leadership and Boston's upgraded roster, the Celtics again advanced to the Conference Finals for a rematch with the 76ers. Boston fell behind 3–1 to start the series but won the next three games to advance to the Finals against the Houston Rockets, winning in six games and earning Bird his first championship. He averaged 21.9 points, 14 rebounds, 6.1 assists, and 2.3 steals per game for the postseason and 15.3 points, 15.3 rebounds, and 7 assists per game for the Finals.
At the 1982 All-Star Game, Bird scored 19 points en route to winning the All-Star Game MVP Award. At the conclusion of the season, he earned his first All-Defensive Team selection. He eventually finished runner-up in Most Valuable Player Award voting to Moses Malone. In the Conference Finals, the Celtics faced the 76ers for the third consecutive year, losing in seven games. Boston's misfortunes continued into the next season, with Bird again finishing second in MVP voting to Malone and the team losing in the Conference Semifinals to the Milwaukee Bucks.