The division was created at the start of the 1970–71 season, when the league expanded from 14 to 17 teams with the addition of the Buffalo Braves, the Cleveland Cavaliers and the Portland Trail Blazers. The league realigned itself into two conferences, the Western Conference and the Eastern Conference, with two divisions in each conference. The Atlantic Division began with four inaugural members, the Celtics, the Braves, the Knicks and the 76ers. The Celtics, the Knicks and the 76ers all joined from the Eastern Division.
The Celtics have won the most Atlantic Division titles with 21. The 76ers have won the second most titles with five. Eight NBA champions came from the Atlantic Division. The Celtics won six championships, while the Knicks and the 76ers won one championship each. All of them, except the 1972–73 Knicks, were division champions. In the 1983–84 season, all five teams from the division qualified for the playoffs. In the 1982–83 season, all teams in the division had winning percentages above 0.500 (50%). The most recent division champion is the Toronto Raptors.
In the aftermath of the Boston Marathon bombings, the NBA canceled the April 16 game scheduled in Boston between the Celtics and the Pacers; the game was not rescheduled because it would have had no impact on either team's playoff seedings.