[1] As a child, Cullum Jr. became enamored of his father's music collection that included recordings by Bix Beiderbecke, Louis Armstrong, Blind Lemon Jefferson, and Lead Belly.
While attending Alamo Heights High School, Cullum played with a small jazz ensemble where his father would occasionally sit in on saxophone.
After interest in the group suddenly grew following their exposure to the HemisFair crowds of 1968, the Cullums sold their grocery business, and devoted themselves full-time to music.
They appeared on Austin City Limits on several occasions, and for 25 years broadcast weekly live performances on over 200 radio stations in the US.
[2] Cullum played with such music legends as Louis Armstrong, Benny Goodman, Pete Fountain, and Earl Hines.
Cullum's career also led him to accompany other jazz artists such as Joe Venuti, Doc Severinsen, Dick Hyman, and Lionel Hampton.
[2] In 2011, Stanford University Libraries acquired Cullum's Riverwalk Jazz archives, comprising over 400 radio show programs.