On November 9, 2012, the Los Angeles Lakers fired Mike Brown after starting the season 1–4 and named Bernie Bickerstaff as interim head coach. This was one of the earliest regular season head coach firings in NBA history. On November 12, 2012, the Lakers hired Mike D'Antoni as official head coach and demoted Bickerstaff back to an assistant head coach.
On December 27, 2012, the Brooklyn Nets fired Avery Johnson after losing 10 out of 13 games in December, which came right after winning the Eastern Conference's Coach of the Month award in November. The team promoted assistant P. J. Carlesimo as interim head coach.
On January 8, 2013, the Milwaukee Bucks and Scott Skiles mutually agreed to part ways after starting the season with a 16–16 record. The team promoted assistant Jim Boylan as interim head coach.
On January 18, 2013, the Phoenix Suns and Alvin Gentry mutually agreed to part ways. The Suns' 13–28 record at the time of Gentry's departure was the worst in the Western Conference. The team promoted assistant and development coach Lindsey Hunter as interim head coach.
The regular season started on October 30, 2012, when the 2011–12 NBA champions Miami Heat defeated the Boston Celtics 120–107. The regular season ended on April 17, 2013. The entire schedule was released on July 26, 2012.
A regular season game took place at the O2 Arena in London, United Kingdom between the Detroit Pistons and the New York Knicks on January 17, 2013. The Knicks won the game 102–87.
The Boston Celtics and Indiana Pacers played 81 games instead of the scheduled 82. A Pacers-Celtics game in Boston was initially postponed in the aftermath of the 2013 Boston Marathon bombing. Because this happened very late in the regular season (leaving little time in which either team could play on a new date in Boston) and the results would not have affected that season's standings, the NBA decided to vacate the game for good.
z – Clinched home court advantage for the entire playoffs
c – Clinched home court advantage for the conference playoffs
y – Clinched division title
x – Clinched playoff spot
† – In the aftermath of the Boston Marathon bombing, 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.
The Los Angeles Clippers clinched #4 seed over Memphis as the Clippers won the Pacific Division and the Grizzlies finished second in the Southwest Division. Also, the Clippers secured home court advantage over the Grizzlies based on head-to-head record (3–1).
The Los Angeles Lakers clinched #7 seed over Houston based on winning percentage against Western Conference teams (the Lakers' .538 to the Rockets' .462).
The New Jersey Nets moved to Brooklyn and became the Brooklyn Nets, returning to the state the team played in when it first joined the NBA from the ABA back in 1976. The Nets now play at the Barclays Center. The first game there would have pitted the Nets against the New York Knicks on November 1, but due to the damage caused by Hurricane Sandy, it was postponed to November 26. Instead the Nets opened the new season in Brooklyn against the Toronto Raptors on November 3, winning the game by a score of 107–100.
The center position in the All-Star Game player balloting was eliminated, beginning with the 2013 game, citing a more perimeter-oriented game and increased use of smaller, faster lineups. Fans can now selected three generic frontcourt players in addition to any two guards.
On December 21, 2012, the Denver Nuggets shot a record-low 0–22 from the three–point area in a 101–93 loss to the Portland Trail Blazers, who originally held that record by going 0–20 a week prior.
On January 16, 2013, LeBron James became the youngest player to reach 20,000 career points, while also reaching 5,000 assists in the same game.
On January 27, 2013, Dirk Nowitzki passed Allen Iverson for 18th place on the NBA's all-time scoring list in a 110–95 victory over the Phoenix Suns. Shawn Marion also played his 1,000th game in the NBA against the team that first drafted him back in 1999, which was a pick that, ironically, was first owned by Dallas.
On February 27, 2013, Stephen Curry scored 54 points but his Warriors lost to the Knicks, 109–105. He shot 18 for 28 from the field, making a Warriors franchise-record 11 three-pointers on 11 of 13 shooting from 3-point range. The 54 points Curry had was the third highest total by a Knicks opponent in the current Madison Square Garden, trailing Kobe Bryant's 61 points on February 2, 2009, and Michael Jordan's 55 points on March 28, 1995. His 54 points were the most anyone recorded in the 2012–13 season. The 11 3-pointers were good for second most all-time in a game, 1 behind the record 12 made by Bryant (1/7/03) and Donyell Marshall (3/13/05).
In a March 12, 2013 game against his former team, the Orlando Magic, Los Angeles Laker Dwight Howard tied his own NBA record of 39 free throw attempts. He made 25 of the 39 attempts. He had previously set the league mark with 39 free throw attempts in a game while playing for the Orlando Magic vs. the Golden State Warriors on January 12, 2012.
On March 27, 2013, the Chicago Bulls ended Miami Heat's 27–game winning streak which began on February 3 when the Heat defeated the Toronto Raptors 100–85. The Bulls won the game 101–97. It was second longest in NBA history, only surpassed by the Lakers' 33-game winning streak in the 1971–72 season until the Golden State Warriors' 28-game winning streak in 2015.
The 2013 Boston Marathon bombing led to the cancellation of the game between the Indiana Pacers and the Boston Celtics, which was originally scheduled for April 16. As both teams' playoff positions were already set, the game was not rescheduled, instead they will force to have a bye. Both teams finished the season with only 81 regular season games, making it the first time in 58 seasons that some teams played more regular season games than others.
Dwight Howard led the league in defensive rebounds for the sixth consecutive season and sixth season overall in his career, both league records. He led the NBA in defensive rebounds every season starting with the 2007–08 season.
This was the final season for the New Orleans Hornets, who announced that they would change their name to the Pelicans, effective in 2013–14. In turn, the team then known as the Charlotte Bobcats would reclaim the Pelicans' former name and records from the original team's tenure in the Queen City, but it would also keep its own records from its 2004 founding up to this point.
^Beck, Howard (October 24, 2012). "The All-Star Center is Officially Extinct". New York Times. Retrieved October 24, 2012. The N.B.A., bowing to new realities in a multi-positional era, has eliminated "center" from its All-Star ballots for the 2012–13 season. Instead, fans will vote for three frontcourt players and two guards.