[13] Hannum is one of only three NBA players to receive more than six personal fouls in a single game (Don Otten and Cal Bowdler are the others).

[15] On July 14, 1951, Hannum was traded by the Syracuse Nationals with Fred Scolari to the Baltimore Bullets for Red Rocha.

A year later, led by Bob Pettit (a hall of famer and member of the NBA 75th Anniversary Team[24]), Cliff Hagan, and Martin, the Hawks went 41–31 and won another division title before advancing to the Finals to play the Boston Celtics.

[28] Coincidentally, the only two seasons in Russell's 13-year career in which the Celtics' center did not win an NBA championship were the direct result of losing to a team coached by Hannum (the 1957-58 Hawks and the 1966-67 Philadelphia 76ers).

[38] Hannum coached the Wichita Vickers of the AAU National Industrial Basketball League in the 1958–59 and 1959–60 season.

[39][40] Hannum returned to the NBA in 1960 with the Syracuse Nationals, advancing to the Eastern Finals in his first season and losing in the first round two years in a row.

[42][43][44] Hannum had expressed interest in coaching the San Francisco Warriors when the team had moved to the region from Philadelphia in 1962.

[45] That year, the Warriors, bolstered by rookie Nate Thurmond to go with Wilt Chamberlain, went 48–32 and advanced all the way to the NBA Finals, losing to the Boston Celtics.

Hannum placed emphasis on changing the offense to rely on scoring in movement, while slowing the game down and playing half court.

This would see the reigning MVP Wilt Chamberlain score a career-low 24.1 points per game but also shoot 68.3% on his field goal attempts.

[48] Hannum had convinced Chamberlain that focusing more on defense and passing would bring the team greater success.

[55] 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.

[52] Hannum then coached the Wilt Chamberlain-led Philadelphia 76ers to the NBA championship, ending the eight-year title streak of the Boston Celtics.

[61][62] Hannum left the team after the season to coach the Oakland Oaks in the newly created American Basketball Association.

[3] In 1968, Hannum was named head coach and executive vice president of the Oakland Oaks (owned by singer Pat Boone along with S. Kenneth Davidson and Dennis A. Murphy) of the second-year American Basketball Association.

[64] Tasked with improving the worst team in the ABA the previous season, Hannum coached the Oaks to 60 wins (jumping out to a 25–4 start) even with the loss of Barry to a knee injury that saw him play 35 games.

[71] Hannum left after the season ended as the Oaks relocated to become the Washington Caps under new management by Earl Foreman.

[72] Hannum was hired to be the head coach of the San Diego Rockets 26 gamed into the 1969–1970 season to replace Jack McMahon.

[73][74][75] One of Hannum's players in San Diego was future Hall of Fame coach Pat Riley.

[34] On April 8, 1971, less than three weeks after the end of season, Hannum left the team, which soon relocated to Houston, Texas.

[78] It was Hannum who instituted changes to the color scheme of the team from orange and black to columbine blue and yellow.

Hannum said he was conducting an experiment because of “the trend of pressure defense...I wanted to see how far you could go without hurting your team's chances.

In addition to Pettit, Chamberlain and Barry, he had also coached Cliff Hagan, Ed Macauley, Slater Martin, Dolph Schayes, Nate Thurmond, Billy Cunningham, Hal Greer, Elvin Hayes, Calvin Murphy, Chet Walker, and Guy Rodgers (for the Warriors).

[90] Hannum, a native of Los Angeles, and graduate of the University of Southern California, died at the age of 78 in San Diego.