Born and raised in Des moines, Iowa, Roberts began his career after service in the US Navy with the Ray Robbins Band, and then quit to join Gene Krupa in 1947, where he was in the same section with Urbie Green. It was Urbie's lyric tenor trombone playing that inspired George to be an "Urbie" one octave lower.
When the Krupa band broke up in 1949, George played freelance in Reno for a year before being hired into the Stan Kenton Orchestra from 1950 until 1953, to replace Bart Varsalona, who had left the band during its 1949-50 hiatus. Roberts opted to stay in Los Angeles rather than go with Kenton on his 1953 European tour.
Working freelance again, he was introduced to Nelson Riddle by Lee Gillette, one of the executives at Capitol Records who had produced Kenton recordings. George soon launched a successful studio recording career with Riddle, Don Costa, Billy May, Axel Stordahl,...