He remained the team's head coach after his playing retirement and led the Warriors to an NBA championship in 1975.

Attles was employed by the Warriors for the rest of his life, serving in roles including team ambassador and community relations representative.

[2] He held a bachelor's degree in Physical Education and History from North Carolina A&T State University.

[3] Before the Warriors drafted him he intended to return to Newark and coach at his local junior high school.

[8] He was a reserve on the 1964 Warriors team (with Wilt Chamberlain and Guy Rodgers) that reached the NBA Finals and lost to the Boston Celtics, four games to one.

[9][10] Attles also played on the Warriors' 1967 team that lost to Chamberlain's 68–13 Philadelphia 76ers in a six-game championship series.

[5] He retired as a player after the 1970–71 season,[5] and stayed on as head coach, guiding the Rick Barry-led Warriors to the 1975 NBA championship over the heavily favored Washington Bullets,[4] making him the second African-American coach to win an NBA title (the first was Bill Russell).

Attles's team tried to repeat the following season, but they lost to the Phoenix Suns in the conference finals in seven games.

Attles tore his Achilles tendon during the 1979–80 season and missed 21 games which were covered by his assistant Johnny Bach.

[20] Attles married his wife, Wilhelmina Rice, in 1964; his Warriors teammate, Wilt Chamberlain, was his best man.