Hannum played at USC, where he was captain of the 1948 team.
Professional career
Hannum played in the NBA between 1949 and 1957. After a season with the Oshkosh All-Stars, followed by the formation of the National Basketball Association, he played for several NBA teams and scored more than 3,000 points.
Coaching career
Hannum coached the Bob Pettit–led St. Louis Hawks team to the 1958 NBA Championship over the Celtics in the NBA Finals. It is one of the only two in Bill Russell's 13-year career in which the Celtics' center did not win an NBA championship. Hannum coached the Wichita Vickers of the AAU National Industrial Basketball League in 1958-1959 and 1959-1960. In 1964, Hannum was named NBA Coach of the Year while with the San Francisco Warriors. In 1966, Hannum was named the head coach of the Philadelphia 76ers. During his first season as coach, the 76ers had a record setting season as they started 46–4, en route to a record of 68–13, the best record in league history at the time. After a 129-103 win over the Pistons on March 3, 1967, he joined Red Auerbach as the only coaches to have won 60 games in a season at that period. Hannum led the Sixers towards the 63rd victory, breaking the NBA-record for most wins in a single season, in an OT win over the Boston Celtics. On March 14, 1967, he became the first coach to have won 65 games in a season. Hannum then coached the Wilt Chamberlain-led Philadelphia 76ers to the NBA championship, ending the eight-year title streak of the Boston Celtics. The 1967 Championship made him the first of only three head coaches in NBA history to win championships with two different teams. In 1968 Hannum was named head coach and executive vice president of the Oakland Oaks of the American Basketball Association. Hannum coached the Rick Barry-led Oaks to the 1969 ABA Championship, becoming the first of two coaches to win championships in both the NBA and ABA. Hannum won the ABA Coach of the Year honors the same season. Hannum on April 8, 1971, left his position as head coach of the San Diego Rockets of the NBA to become President, General Manager and head coach of the ABA's Denver Rockets. In his first season the Rockets lost their opening playoff match to the Texas Chaparrals. On June 13, 1972 Hannum bought control of the Rockets with A.G. "Bud" Fischer and Frank M. Goldberg. In the 1972–73 season Hannum coached the Rockets to the 1973 ABA Playoffs where they lost in the first round of the Western Division playoffs to the Indiana Pacers, 4 games to 1. Hannum returned the Rockets to the 1974 ABA Playoffs where they lost to the San Diego Conquistadors. On April 30, 1974 Hannum was dismissed as president, general manager and head coach of the Rockets. Hannum's combined record, was 649–564 with a 61–46 record in the playoffs on 11 trips in 16 seasons.
Hannum is one of only three NBA players to receive more than six personal fouls in a single game. On December 26, 1950, Hannum received seven personal fouls in a game against the Boston Celtics.