Bass' professional coaching career started with the ABA's Denver Rockets (now the Denver Nuggets) in 1967, which he coached for two years. He coached college basketball at Texas Tech for a season-and-a-half from 1969 to 1971. He coached The Floridians of the ABA for two years before the team folded at the end of the 1972 season. The next season he coached the Memphis Tams; and, at the beginning of the 1974/75 season, Bass was hired by the ABA's San Antonio Spurs, which he coached for nearly two seasons, until the franchise moved into the NBA in 1976 as part of the ABA–NBA merger.
At that point, Bass moved into the Spurs' front office, assuming the role of general manager. He would, over the years with the team, assume coaching duties on an interim basis as needed—in 1980, 1984, and 1992. He finished his coaching career with a 311-300 record. At the conclusion of the 1989/90 season, Bass won the NBA Executive of the Year Award. Bass would then take a general manager position with the Charlotte Hornets in 1995; in that capacity he would win the award again in 1997. Bass retired in 2004 (by which time the Hornets had relocated to New Orleans).
Bass served as the head basketball coach at Oklahoma Baptist for 15 years and was named the NAIA Coach of the Year in 1966, when his team won the NAIA national title.
Bass was hired has head coach of the Texas Tech Red Raiders replacing Gene Gibson. Bass cited a challenge to return to the college game and a distaste for the long pro season and its demands on his time away from family for accepting the position of head coach at Texas Tech.
In his first season, the Red Raiders posted a 14–10 record under Bass and finished third in the Southwest Conference (SWC) regular season standings. The 1969–70 team posted the first winning season for the Red Raiders in four years.
National champion Postseason invitational champion Conference regular season champion Conference regular season and conference tournament champion Division regular season champion Division regular season and conference tournament champion Conference tournament champion