Alex was a 1942 All-City player at Hamilton HS in West LA and then went to USC where he was captain of the 1948 Trojan squad and was selected All-PCC, after missing three years in military service for World War II. The 6-7 Hannum was a 4th round professional draft pick and played for nine years, scoring over 3000 points and grabbing over 2000 rebounds before going into coaching, which he is most noted for. He was a professional coach for 16-years, winning two NBA and one ABA title (the first to win titles in both leagues), winning 649 games in his career, and was coach of the year in both leagues.

He was second to Red Auerbach to win 60 games in a season, and ended the Celtics 8-year title run, winning the 1967 title with Wilt Chamberlain and becoming the first to win NBA titles with two different teams (Phil Jackson and Pat Riley have joined him). He coached at least 14 other members of the Naismith Basketball Hall of Fame. He was inducted into the Los Angeles City Athletics HOF in 2011, and the Naismith Basketball Hall of Fame in 1998. He passed away on January 18, 2002 in San Diego.