Steve Kerr coached the Golden State Warriors to an NBA-record 73 wins in the 2015–16 regular season.
Golden State finished 73–9, surpassing the 1995–96 Chicago Bulls’ previous record of 72–10. The record-breaking 73rd victory came on April 13, 2016, when the Warriors defeated the Memphis Grizzlies 125–104 at Oracle Arena. Kerr’s team also became the first NBA club to complete a regular season without suffering consecutive losses.
Kerr missed the start of that season while recovering from back surgery, so assistant Luke Walton served as acting head coach for the first 43 games. Kerr returned in January and officially remained the head coach, making him the canonical answer to the question. He was later named the 2015–16 NBA Coach of the Year.
The regular-season record did not produce a championship. Golden State reached the Finals but lost a 3–1 series lead to the Cleveland Cavaliers, who became the first team to overcome that deficit in an NBA Finals. Stephen Curry won the regular-season MVP award, while Andre Iguodala was Finals MVP for the previous championship season.