Atkinson joined the New York Knicks coaching staff as an assistant coach under
Mike D'Antoni on August 6, 2008. In 2012, after four seasons with the Knicks, he joined the
Atlanta Hawks coaching staff under
Mike Budenholzer. On April 17, 2016, it was announced that Atkinson would become the head coach of the
Brooklyn Nets, beginning after the Hawks' postseason ended.
Brooklyn Nets (2016–2020) Atkinson made his NBA head coaching debut on October 26, 2016, in a 122–117 loss to the
Boston Celtics. He got his first win as an NBA head coach two days later when the Nets defeated the
Indiana Pacers 103–94. The Nets finished the season with a 20–62 record, with a 0–10 record in February 2017.
Brook Lopez left the team in Atkinson's second season; Lopez was traded to the
Los Angeles Lakers in an off-season deal. The Nets were competitive for the early part of the season before going 1–9 in February, ending any chance to be in the playoffs. They finished the season with a 28–54 record, which was an eight-game improvement from the previous season. In Atkinson's third season with the Nets he led the team to a 42–40 record, winning 14 games more than the previous season, and a playoff berth with the sixth seed. The Nets lost to the
Philadelphia 76ers in five games in the first round of the playoffs. In Atkinson's fourth season with the Nets he led the team to a 28–34 record, before stepping down as head coach on March 7, 2020.
Los Angeles Clippers (2020–2021) On November 16, 2020, Atkinson was hired as an assistant coach for the
Los Angeles Clippers under head coach
Tyronn Lue.
Golden State Warriors (2021–2024) On August 13, 2021, the
Golden State Warriors hired Atkinson as an assistant coach. He won his first
NBA championship as the Warriors defeated the
Boston Celtics in six games in the
2022 NBA Finals. During the NBA Finals, the
Charlotte Hornets offered Atkinson the position of head coach, but he reportedly turned it down after informally agreeing to take the job. On February 12, 2024, Atkinson coached the Warriors to a 129–107 victory against the
Utah Jazz while head coach
Steve Kerr attended
Dejan Milojević's funeral in
Serbia.
Cleveland Cavaliers (2024–present) On June 28, 2024, Atkinson was hired by the
Cleveland Cavaliers as head coach. The Cavaliers started the
2024–25 season with one of the longest winning streaks in NBA history, winning their first 15 games, which made Atkinson the only head coach in NBA history to win the first 15 games to start a tenure with a franchise, as Cleveland would not suffer their first loss until November 19 on the road against the defending champion, the
Boston Celtics. In April 2025, Atkinson won the
NBCA Coach of the Year Award after he led the Cavaliers to a 64–18 record during the regular season. On May 5, he was named
NBA Coach of the Year. ==Head coaching record==